RÉSUMÉ
The aim of this study was to analyze the effects of non-genetic factors on the estimation of genetic parameters of early growth traits in hybrid mutton sheep using ASReml software, in order to provide theoretical basis for screening the optimal hybriding combinations and accelerating the breeding process of new breeds of specialized housed-feeding mutton sheep. We selected the wellgrown hybrid Southhu (Southdown × Hu sheep) and Dorhu (Dorset × Hu sheep) sheep as the research objects, constructed weight correction formulae for SH and DH sheep at 60 and 180 days; and used ASReml software to investigate the effects of non-genetic factors on the estimation of genetic parameters of early growth traits in hybrid sheep. The results showed that the birth month and birth type were found significant for all traits (p < 0.001); the heritability of maternal effects ranged from 0.0709 to 0.1859. It was found that both SH and DH sheep emerged the potential for rapid early growth and development, early growth traits are significantly affected by maternal genetic effects, thereby the maternal effect should be taken into consideration for the purpose of improving accuracy in parameter estimations and therefore increasing the success of breeding programs.
Sujet(s)
Sélection , Animaux , Ovis/génétique , Femelle , Hybridation génétique/génétique , Logiciel , Mâle , Poids/génétique , Ovis aries/génétique , Ovis aries/croissance et développement , Ovis aries/physiologieRÉSUMÉ
Hybridization has been recognized to play important roles in evolution, however studies of the genetic consequence are still lagging behind in vertebrates due to the lack of appropriate experimental systems. Fish of the genus Xiphophorus are proposed to have evolved with multiple ancient and ongoing hybridization events. They have served as an informative research model in evolutionary biology and in biomedical research on human disease for more than a century. Here, we provide the complete genomic resource including annotations for all described 26 Xiphophorus species and three undescribed taxa and resolve all uncertain phylogenetic relationships. We investigate the molecular evolution of genes related to cancers such as melanoma and for the genetic control of puberty timing, focusing on genes that are predicted to be involved in pre-and postzygotic isolation and thus affect hybridization. We discovered dramatic size-variation of some gene families. These persisted despite reticulate evolution, rapid speciation and short divergence time. Finally, we clarify the hybridization history in the entire genus settling disputed hybridization history of two Southern swordtails. Our comparative genomic analyses revealed hybridization ancestries that are manifested in the mosaic fused genomes and show that hybridization often preceded speciation.
Sujet(s)
Cyprinodontiformes , Évolution moléculaire , Spéciation génétique , Hybridation génétique , Phylogenèse , Animaux , Cyprinodontiformes/génétique , Cyprinodontiformes/classification , Génomique/méthodes , Génome/génétiqueRÉSUMÉ
Haldane's rule occupies a special place in biology as one of the few 'rules' of speciation, with empirical support from hundreds of species. And yet, its classic purview is restricted taxonomically to the subset of organisms with heteromorphic sex chromosomes. I propose explicit acknowledgement of generalized hypotheses about Haldane's rule that frame sex bias in hybrid dysfunction broadly and irrespective of the sexual system. The consensus view of classic Haldane's rule holds that sex-biased hybrid dysfunction across taxa is a composite phenomenon that requires explanations from multiple causes. Testing of the multiple alternative hypotheses for Haldane's rule is, in many cases, applicable to taxa with homomorphic sex chromosomes, environmental sex determination, haplodiploidy, and hermaphroditism. Integration of a variety of biological phenomena about hybrids across diverse sexual systems, beyond classic Haldane's rule, will help to derive a more general understanding of the contributing forces and mechanisms that lead to predictable sex biases in evolutionary divergence and speciation.
Sujet(s)
Processus de détermination du sexe , Processus de détermination du sexe/génétique , Mâle , Animaux , Femelle , Chromosomes sexuels/génétique , Hybridation génétique , Spéciation génétique , Évolution biologiqueRÉSUMÉ
This study spanned 6 years and 4 generations, involving the progressive crossbreeding of South African Kalahari Goat (SK) and Guizhou Black Goat (GB) over three generations, followed by cross fixation F3 with F1 in the fourth generation, accompanied by the use of molecular markers technology to select a high fertility population, resulting in the creation of a hybrid goat, BKF4 (11/16 SK lineage and 5/16 GB lineage). A comparative evaluation of the BKF4 hybrid breed and its parental breeds was conducted. Reproductive and production parameters of GB, SK, and BKF4 goat groups were monitored, including lambing rate (LR), survival rate (SR), daily weight gain at 3 months of age (DWG), and adult body weight (ABW) (n = 110, 106, 112 per group). In addition, dressing percentage (DP) (n = 12 per group) and analyses of amino acids (n = 8, 6, 10 per group) and fatty acids (n = 6 per group) were conducted to evaluate meat quality indicators. Results: (1) Reproductive and production performance: The index of LR reached 199%, significantly higher than GB and SK (p ≤ 0.001), with a SR of 95.0%, markedly higher than SK (p ≤ 0.001); DWG was 276.5 g, ABW reached 56.6 kg and with a dressing percentage (DP) of 54.5%, they are significantly surpassing GB (p ≤ 0.001). (2) Regarding meat quality: pH45-value and crude protein content (CP) increased, while intramuscular fat content increased compared to GB and ash content decreased. The amino acid composition was similar to GB, but the taste was more similar to SK. However, there were some negative impacts on fatty acid composition and functionality. (3) PCA analysis revealed that: BKF4 exhibited superior meat quality compared to GB and SK, influenced by two key factors contributing 83.49% and 16.51% to the explained variance, respectively. The key factors affecting meat quality include intramuscular fat (IMF), nutrient index (NI), PUFAs/MUFAs, n-6FAs, and drip loss (DL).
Sujet(s)
Capra , Viande , Animaux , Capra/génétique , Viande/analyse , Viande/normes , Mâle , Femelle , Hybridation génétique , Acides gras/métabolisme , Acides gras/analyse , République d'Afrique du Sud , Sélection , Acides aminés/analyse , Acides aminés/métabolisme , Reproduction , PoidsRÉSUMÉ
BACKGROUND: A correct and stably expressing reference gene is prerequisite for successful quantitative real-time PCR (qRT-PCR). Investigating gene expression profiling during flower development could enhance our understanding of the molecular mechanisms of flower formation and fertility in Lycium. METHODS AND RESULTS: In this study, 11 candidate reference genes in Lycium flower development were selected from transcriptome sequence data and evaluated with five traditional housekeeping genes from previous studies based on qRT-PCR amplification. Comparing the expression stability result of 16 candidate genes using GeNorm, NormFinder, BestKeeper, and Delta Ct algorithms, Lba04g01649 and Lba12g02820 were validated as the optimal reference genes for the flower development of Lycium. CONCLUSIONS: The reference genes identified in this study would improve the accuracy of qRT-PCR quantification of target gene expression in Lycium flower development and facilitate future functional genomics studies on flower development. This research could lay the foundation for the study of the reproduction and development of the Lycium flower.
Sujet(s)
Fleurs , Analyse de profil d'expression de gènes , Régulation de l'expression des gènes végétaux , Gènes de plante , Lycium , Réaction de polymérisation en chaine en temps réel , Normes de référence , Lycium/génétique , Lycium/croissance et développement , Fleurs/génétique , Fleurs/croissance et développement , Réaction de polymérisation en chaine en temps réel/méthodes , Réaction de polymérisation en chaine en temps réel/normes , Régulation de l'expression des gènes végétaux/génétique , Analyse de profil d'expression de gènes/méthodes , Analyse de profil d'expression de gènes/normes , Transcriptome/génétique , Gènes essentiels/génétique , Hybridation génétiqueRÉSUMÉ
MAIN CONCLUSION: Using octoploid somatic hybrids with excessive C genome sets, AABBCCCC, a diverse allohexaploid, AABBCC, was produced by C genome reduction through subsequent crossing with various AABB cultivars. Even when somatic hybrids are produced, the plants that are produced are rarely in themselves an innovative crop. In this study, we used somatic hybrids of Brassica juncea (AABB) and B. oleracea (CC) as model cases for the genetic diversification of the somatic hybrids. One cell of 'Akaoba Takana' (B. juncea) and two cells of 'Snow Crown' (B. oleracea) were fused to create several somatic hybrids with excessive C genomes, AABBCCCC. Using AABBCCCC somatic hybrids as mother plants and crossing with 'Akaoba Takana', the AABBCC progenies were generated. When these AABBCC plants were self-fertilized, and flow cytometric (FCM) analysis was performed on the next generations, differences in the relative amount of genome size variation were observed, depending on the different AABBCCCC parents used for AABBCC creation. Further self-progeny was obtained for AABBCC plants with a theoretical allohexaploid DNA index by FCM. However, as the DNA indices of the progeny populations varied between plants used and aneuploid individuals still occurred in the progeny populations, it was difficult to say that the allohexaploid genome was fully stabilized. Next, to obtain genetic diversification of the allohexaploid, different cultivars of B. juncea were crossed with AABBCCCC, resulting in diverse AABBCC plants. Genetic diversity can be further expanded by crossbreeding plants with different AABBCC genome sets. Although genetic stability is necessary to ensure in the later generations, the results obtained in this study show that the use of somatic hybrids with excess genomes is an effective strategy for creating innovative crops.
Sujet(s)
Brassica , Génome végétal , Hybridation génétique , Polyploïdie , Génome végétal/génétique , Brassica/génétique , Moutarde (plante)/génétique , Variation génétique , Taille du génomeRÉSUMÉ
Disentangling the genomic intricacies underlying speciation and the causes of discordance between sources of evidence can offer remarkable insights into evolutionary dynamics. The ant-eating spider Zodarion nitidum, found across the Middle East and Egypt, displays yellowish and blackish morphs that co-occur sympatrically. These morphs additionally differ in behavioral and physiological features and show complete pre-mating reproductive isolation. In contrast, they possess similar sexual features and lack distinct differences in their mitochondrial DNA. We analyzed both Z. nitidum morphs and outgroups using genome-wide and additional mitochondrial DNA data. The genomic evidence indicated that Yellow and Black are reciprocally independent lineages without signs of recent admixture. Interestingly, the sister group of Yellow is not Black but Z. luctuosum, a morphologically distinct species. Genomic gene flow analyses pinpointed an asymmetric nuclear introgression event, with Yellow contributing nearly 5 % of its genome to Black roughly 320,000 years ago, intriguingly aligning with the independently estimated origin of the mitochondrial DNA of Black. We conclude that the blackish and yellowish morphs of Z. nitidum are long-diverged distinct species, and that the ancient and modest genomic introgression event registered resulted in a complete mitochondrial takeover of Black by Yellow. This investigation underscores the profound long-term effects that even modest hybridization events can have on the genome of organisms. It also exemplifies the utility of phylogenetic networks for estimating historical events and how integrating independent lines of evidence can increase the reliability of such estimations.
Sujet(s)
ADN mitochondrial , Hybridation génétique , Phylogenèse , Araignées , Sympatrie , Animaux , Araignées/génétique , Araignées/classification , ADN mitochondrial/génétique , Flux des gènes , Spéciation génétiqueRÉSUMÉ
Polyploids are essential in plant evolution and species formation, providing a rich genetic reservoir and increasing species diversity. Complex polyploids with higher ploidy levels often have a dosage effect on the phenotype, which can be highly detrimental to gametes, making them rare. In this study, offspring plants resulting from an autoallotetraploid (RRRC) derived from the interspecific hybridization between allotetraploid Raphanobrassica (RRCC, 2n = 36) and diploid radish (RR, 2n = 18) were obtained. Fluorescence in situ hybridization (FISH) using C-genome-specific repeats as probes revealed two main genome configurations in these offspring plants: RRRCC (2n = 43, 44, 45) and RRRRCC (2n = 54, 55), showing more complex genome configurations and higher ploidy levels compared to the parental plants. These offspring plants exhibited extensive variation in phenotypic characteristics, including leaf type and flower type and color, as well as seed and pollen fertility. Analysis of chromosome behavior showed that homoeologous chromosome pairing events are widely observed at the diakinesis stage in the pollen mother cells (PMCs) of these allopolyploids, with a range of 58.73% to 78.33%. Moreover, the unreduced C subgenome at meiosis anaphase II in PMCs was observed, which provides compelling evidence for the formation of complex allopolyploid offspring. These complex allopolyploids serve as valuable genetic resources for further analysis and contribute to our understanding of the mechanisms underlying the formation of complex allopolyploids.
Sujet(s)
Aneuploïdie , Chromosomes de plante , Polyploïdie , Raphanus , Raphanus/génétique , Chromosomes de plante/génétique , Hybridation fluorescente in situ , Brassica/génétique , Hybridation génétique , Méiose/génétique , Génome végétal , Pollen/génétique , PhénotypeRÉSUMÉ
BACKGROUND: Inter-subspecific hybrid rice represents a significant breakthrough in agricultural genetics, offering higher yields and better resilience to various environmental stresses. While the utilization of these hybrids has shed light on the genetic processes underlying hybridization, understanding the molecular mechanisms driving heterosis remains a complex and ongoing challenge. Here, chromatin immunoprecipitation-sequencing (ChIP-seq) was used to analyze genome-wide profiles of H3K4me3 and H3K27me3 modifications in the inter-subspecific hybrid rice ZY19 and its parents, Z04A and ZHF1015, then combined them with the transcriptome and DNA methylation data to uncover the effects of histone modifications on gene expression and the contribution of epigenetic modifications to heterosis. RESULTS: In the hybrid, there were 8,126 and 1,610 different peaks for H3K4me3 and H3K27me3 modifications when compared to its parents, respectively, with the majority of them originating from the parental lines. The different modifications between the hybrid and its parents were more frequently observed as higher levels in the hybrid than in the parents. In ZY19, there were 476 and 84 allele-specific genes with H3K4me3 and H3K27me3 modifications identified, representing 7.9% and 12% of the total analyzed genes, respectively. Only a small portion of genes that showed differences in parental H3K4me3 and H3K27me3 modifications which demonstrated allele-specific histone modifications (ASHM) in the hybrid. The H3K4me3 modification level in the hybrid was significantly lower compared to the parents. In the hybrid, DNA methylation occurs more frequently among histone modification target genes. Additionally, over 62.58% of differentially expressed genes (DEGs) were affected by epigenetic variations. Notably, there was a strong correlation observed between variations in H3K4me3 modifications and gene expression levels in the hybrid and its parents. CONCLUSION: These findings highlight the substantial impact of histone modifications and DNA methylation on gene expression during hybridization. Epigenetic variations play a crucial role in controlling the differential expression of genes, with potential implications for heterosis.
Sujet(s)
Code histone , Vigueur hybride , Hybridation génétique , Oryza , Feuilles de plante , Vigueur hybride/génétique , Oryza/génétique , Oryza/métabolisme , Feuilles de plante/génétique , Feuilles de plante/métabolisme , Histone/métabolisme , Histone/génétique , Épigenèse génétique , Méthylation de l'ADN , Régulation de l'expression des gènes végétauxRÉSUMÉ
Heterosis is the phenomenon that the hybrid offspring outperform two-parent population. Hybridisation has been widely used in plant and animal production as it effectively improves the growth and developmental performance, reproductive performance and disease resistance of the offspring. Hybridization can effectively improve the growth and development performance, reproductive performance and disease resistance of offspring, so it is widely used in animal and plant production. Researchers have used cross-breeding techniques to cultivate excellent new agricultural and animal husbandry strains and supporting lines such as super-excellent Chaoyou 1000 hybrid rice, Xiaoyan No.6 hybrid wheat, Dumeng sheep, and Shanxia black pigs. However, there are still some urgent problems in the current hybrid dominance research: the existing hybrid dominance theory can only partially explain the phenomenon of plant and animal hybrid dominance, and the theory of animal hybrid dominance is less researched, and the accuracy of the existing hybrid dominance prediction methods is limited. China is the world's largest pork production and consumption country. Heterosis can effectively improve the production performance of pigs, and its application in the pig industry has important economic and research value. However, the existing research on pig hybrid production is in its infancy and needs to be further studied. In this review, we summarize the existing heterosis theory, heterosis prediction methods, and their application in pig production, to provide a reference for the application of heterosis in pig breeding.
Sujet(s)
Vigueur hybride , Animaux , Suidae/génétique , Hybridation génétique , Élevage/méthodes , Sélection/méthodesRÉSUMÉ
BACKGROUND: Over the last two decades, hybridization has been a powerful tool used to construct superior yeast for brewing and winemaking. Novel hybrids were primarily constructed using at least one Saccharomyces cerevisiae parent. However, little is known about hybrids used for other purposes, such as targeted flavor production, for example, 2-phenylethanol (2-PE). 2-PE, an aromatic compound widely utilised in the food, cosmetic, and pharmaceutical industries, presents challenges in biotechnological production due to its toxic nature. Consequently, to enhance productivity and tolerance to 2-PE, various strategies such as mutagenesis and genetic engineering are extensively explored to improved yeast strains. While biotechnological efforts have predominantly focused on S. cerevisiae for 2-PE production, other Saccharomyces species and their hybrids remain insufficiently described. RESULTS: To address this gap, in this study, we analysed a new interspecies yeast hybrid, II/6, derived from S. uvarum and S. kudriavzevii parents, in terms of 2-PE bioconversion and resistance to its high concentration, comparing it with the parental strains. Two known media for 2-PE biotransformation and three different temperatures were used during this study to determine optimal conditions. In 72 h batch cultures, the II/6 hybrid achieved a maximum of 2.36 ± 0.03 g/L 2-PE, which was 2-20 times higher than the productivity of the parental strains. Our interest lay not only in determining whether the hybrid improved in productivity but also in assessing whether its susceptibility to high 2-PE titers was also mitigated. The results showed that the hybrid exhibited significantly greater resistance to the toxic product than the original strains. CONCLUSIONS: The conducted experiments have confirmed that hybridization is a promising method for modifying yeast strains. As a result, both 2-PE production yield and tolerance to its inhibitory effects can be increased. Furthermore, this strategy allows for the acquisition of non-GMO strains, alleviating concerns related to additional legislative requirements or consumer acceptance issues for producers. The findings obtained have the potential to contribute to the development of practical solutions in the future.
Sujet(s)
Alcool phénéthylique , Saccharomyces , Alcool phénéthylique/métabolisme , Alcool phénéthylique/analogues et dérivés , Saccharomyces/génétique , Saccharomyces/métabolisme , Fermentation , Hybridation génétique , Génie métabolique/méthodes , Saccharomyces cerevisiae/métabolisme , Saccharomyces cerevisiae/génétique , PichiaRÉSUMÉ
Understanding the sex determination pathway and its disruptions in mosquitoes is critical for the effective control of disease vectors through genetic manipulations based on sex separation. When male hybrids of Aedes aegypti females and Ae. mascarensis males are backcrossed to Ae. aegypti females, a portion of the backcross progeny manifests as males with abnormal sexual differentiation. We discovered a significant correlation between pupal abnormalities and the feminization of subsequent adults exemplified by the relative abundance of ovarian and testicular tissues. All intersex individuals were genetic males as they expressed a male determining factor, Nix. Further, our analysis of the sex-specific splicing of doublesex and fruitless transcripts demonstrated the presence of both male and female splice variants indicating that sex determination is disrupted. A comparative transcriptomic analysis revealed similar expression levels of most female-associated genes in reproductive organs and carcasses between intersexual males and normal females. Moreover, intersexes had largely normal gene expression in testes but significant gene downregulation in male accessory glands when compared with normal males. We conclude that evolving hybrid incompatibilities between Ae. aegypti and Ae. mascarensis involve disruption of sex determination and are accompanied by changes in gene expression associated with sexual differentiation.
Sujet(s)
Aedes , Processus de détermination du sexe , Animaux , Aedes/génétique , Aedes/physiologie , Aedes/croissance et développement , Mâle , Processus de détermination du sexe/génétique , Femelle , Hybridation génétique , Différenciation sexuelle/génétiqueRÉSUMÉ
Crossbreeding aims to increase the productivity of local or indigenous animals by introducing exotic breeds. This study aims to assess the effects of crossbreeding using 50% Boer bucks crossed with Ethiopian indigenous Woyto-Guji goats and to evaluate farmers' perceptions towards crossbred kids. Data were collected from five purposively selected districts in southern Ethiopia. Personal interviews, focus group discussions (FGDs), and field observations were employed to gather information on the goat production systems and farmers' perceptions. The mean ± SD of goat flock size in the study area were 7.31 ± 5.89 heads per household (HH) with larger flock sizes observed in the Alaba zone (10.32 ± 6.56). Goats in the studied areas were primarily kept for income generation. The average age at first kidding was 11.3 ± 1.3 months. Relatively better management practices were observed for crossbred goats in the Alaba, Loko Abaya, and Gurage zones. Respondent farmers highly appreciated Boer crossbred goats due to their superior perception of attractive coat color (4.39 times greater, P < 0.001), docile behavior (3.59 times greater, P < 0.001), fast growth rate (1.64 times greater, P < 0.05), and market preference (5.81 times greater, P < 0.001). However, susceptibility to disease and drought was considered as drawbacks of crossbred kids in the studied areas. It was also reported that crossbreed goats fetched better prices than indigenous goats of a similar age group and under the same management system. All visited farmers expressed a strong interest in crossbreeding. Based on these findings, it can be concluded that Boer crossbred goats perform well in southern Ethiopia. Therefore, the continued production of crossbred kids can be disseminated to these areas. Additionally, it is suggested to consider the interests of goat producers in the remaining areas. Integrated improved management systems need to be implemented to enhance the survival of crossbred kids. Sustainable training programs should be organized for goat keepers, focusing on aspects such as crossbreeding, minimizing inbreeding, buck rotation, and improved feeding and management practices.
Sujet(s)
Agriculteurs , Capra , Reproduction , Animaux , Capra/physiologie , Éthiopie , Reproduction/physiologie , Élevage/méthodes , Femelle , Hybridation génétique , Mâle , Humains , SélectionRÉSUMÉ
Big-bracted dogwoods are popular ornamental trees known for their beautiful spring blooms with showy bracts and four-season appeal. The two most widely grown species are Cornus florida and Cornus kousa, native to Eastern North America and East Asia. Despite their horticultural prominence, there is little information available regarding genetic diversity, population structure, relatedness, and subspecies origins of dogwood cultivars. In this study, 313 cultivars, wild-collected plants, and Rutgers University breeding selections, focusing on C. florida, C. kousa, and interspecific hybrids, were genotyped using restriction-site associated DNA sequencing (RADseq) generating thousands of single nucleotide polymorphism (SNP) and insertion deletion (Indel) markers. The research results showed high genetic diversity among C. florida and C. kousa wild-collected plants and cultivars. For C. florida, pink-bracted plants formed a distinct clade from those with white-bracts with the Mexican C. florida ssp. urbiniana forming an outgroup. For C. kousa, Chinese-collected plants (ssp. chinensis) were a distinct subspecies with clear separation from Japanese and Korean accessions (ssp. kousa) and cultivars were designated as ssp. chinensis, ssp. kousa, or ssp. hybrid. Using this information, a Kompetitive allele specific PCR (KASP) assay genotyping panel was designed to determine C. kousa trees' subspecies makeup. Results revealed many cases of genetically identical cultivars being sold under different names, especially for pink-bracted cultivars of both species. Additionally, reported parent-progeny relationships were evaluated and either validated or discredited. Finally, the hybrid germplasm analysis validated pedigrees of interspecific F1 hybrids and found many of the recent Rutgers breeding selections contain small regions of pacific dogwood (C. nuttallii) DNA introgressed into C. kousa backgrounds. This diversity study elucidates origins, diversity, and relationships of a large population of big-bracted dogwoods. The results can inform plant breeders, arboreta, and the ornamental plant industry, as most modern cultivars and popular historic cultivars are represented.
Sujet(s)
Cornus , Variation génétique , Polymorphisme de nucléotide simple , Cornus/génétique , Cornus/classification , Génotype , Analyse de séquence d'ADN , Phylogenèse , Hybridation génétique , ADN des plantes/génétiqueRÉSUMÉ
Interbreeding and introgression between recently diverged species is common. However, the processes that prevent these species from merging where they co-occur are not well understood. We studied the mechanisms that allowed an isolated group of populations of the snail Helix thessalica to persist within the range of the related Helix pomatia despite high gene flow. Using genomic cline analysis, we found that the nuclear gene flow between the two taxa across the mosaic hybrid zone was not different from that expected under neutral admixture, but that the exchange of mtDNA was asymmetric. Tests showed that there is relaxed selection in the mitochondrial genome of H. thessalica and that the substitution rate is elevated compared to that of H. pomatia. A lack of hybrids that combine the mtDNA of H. thessalica with a mainly (>46%) H. pomatia genomic background indicates that the nuclear-encoded mitochondrial proteins of H. pomatia are not well adapted to the more rapidly evolving proteins and RNAs encoded by the mitochondrion of H. thessalica. The presumed reduction of fitness of hybrids with the fast-evolving mtDNA of H. thessalica and a high H. pomatia ancestry, similar to 'Darwin's Corollary to Haldane's rule', resulted in a relative loss of H. pomatia nuclear ancestry compared to H. thessalica ancestry in the hybrid zone. This probably prevents the H. thessalica populations from merging quickly with the surrounding H. pomatia populations and supports the hypothesis that incompatibilities between rapidly evolving mitochondrial genes and nuclear genes contribute to speciation.
Sujet(s)
ADN mitochondrial , Flux des gènes , , Hybridation génétique , Animaux , ADN mitochondrial/génétique , /génétique , Génome mitochondrial , Aptitude génétique , Évolution moléculaire , Génétique des populations , Mitochondries/génétique , Sélection génétiqueRÉSUMÉ
Hybridization between divergent lineages can result in losses of distinct evolutionary taxa. Alternatively, hybridization can lead to increased genetic variability that may fuel local adaptation and the generation of novel traits and/or taxa. Here, we examined single-nucleotide polymorphisms generated using genotyping-by-sequencing in a population of Dolly Varden char (Pisces: Salmonidae) that is highly admixed within a contact zone between two subspecies (Salvelinus malma malma, Northern Dolly Varden [NDV] and S. m. lordi, Southern Dolly Varden [SDV]) in southwestern Alaska to assess the spatial distribution of hybrids and to test hypotheses on the origin of the admixed population. Ancestry analysis revealed that this admixed population is composed of advanced generation hybrids between NDV and SDV or advanced backcrosses to SDV; no F1 hybrids were detected. Coalescent-based demographic modelling supported the origin of this population about 55,000 years ago by secondary contact between NDV and SDV with low levels of contemporary gene flow. Ancestry in NDV and SDV varies within the watershed and ancestry in NDV was positively associated with distance upstream from the sea, contingent on habitat-type sampled, and negatively associated with the number of migrations that individual fish made to the sea. Our results suggest that divergence between subspecies over hundreds of thousands of years may not be associated with significant reproductive isolation, but that elevated diversity owing to hybridization may have contributed to adaptive divergence in habitat use and life history.
Sujet(s)
Flux des gènes , Génétique des populations , Hybridation génétique , Polymorphisme de nucléotide simple , Animaux , Alaska , Polymorphisme de nucléotide simple/génétique , Truite/génétique , Truite/classification , GénotypeRÉSUMÉ
TGF-ß1/Smads is a classic signaling pathway, which plays important roles in the development process of organisms. Black porgy Acanthopagrus schlegelii and red porgy Pagrus major are valuable economic fishes, and their hybrid offspring show excellent heterosis traits. Yet the molecular regulation mechanism of the heterosis traits is less clear. Here, we explored the TGF-ß1/Smads pathway's molecular genetic information for heterosis in A. schlegelii â × P. major â (AP) and A. schlegelii â × P. major â (PA) in terms of growth and development. The mRNA expression levels of TGF-ß1, TßR-I, TßR-II, and Smad2 genes in different developmental stages of A. schlegelii were detected. Furthermore, the expression levels of TGF-ß1, TßR-I, TßR-II, and Smad2 genes in different tissues of adult (mRNA level) and larva (mRNA and protein level) of A. schlegelii, P. major, and their hybrids were determined by both real-time quantitative PCR and Western blot techniques. The results indicated the ubiquitous expression of these genes in all developmental stages of A. schlegelii and in all tested tissues of A. schlegelii, P. major, and its hybrids. Among them, the mRNA of TGF-ß1, TßR-I, and TßR-II genes is highly expressed in the liver, gill, kidney, and muscle of black porgy, red porgy, and their hybrid offspring. There are significant changes in gene and protein expression levels in hybrid offspring, which indirectly reflect hybrid advantage. In addition, there was no correlation between protein and mRNA expression levels of Smad2 protein. The results provide novel data for the differential expression of growth and development genes between the reciprocal hybridization generation of black porgy and red porgy and its parents, which is conducive to further explaining the molecular regulation mechanism of heterosis in the growth and development of hybrid porgy.
Sujet(s)
Vigueur hybride , Protéine Smad2 , Facteur de croissance transformant bêta-1 , Animaux , Protéine Smad2/génétique , Protéine Smad2/métabolisme , Vigueur hybride/génétique , Facteur de croissance transformant bêta-1/génétique , Facteur de croissance transformant bêta-1/métabolisme , Protéines de poisson/génétique , Protéines de poisson/métabolisme , Hybridation génétique , Récepteur de type I du facteur de croissance transformant bêta/génétique , Récepteur de type I du facteur de croissance transformant bêta/métabolisme , Perciformes/génétique , Perciformes/croissance et développement , Perciformes/métabolisme , Récepteur de type II du facteur de croissance transformant bêta/génétique , Récepteur de type II du facteur de croissance transformant bêta/métabolisme , Récepteurs TGF-bêta/génétique , Récepteurs TGF-bêta/métabolisme , Femelle , Mâle , Régulation de l'expression des gènes au cours du développementRÉSUMÉ
When two species hybridize, the two parental genomes are brought together and some alleles might interact for the first time. To date, the extent of the transcriptomic changes in first hybrid generations, along with their functional outcome constitute an important knowledge gap, especially in parasite species. Here we explored the molecular and functional outcomes of hybridization in first-generation hybrids between the blood fluke parasites Schistosoma haematobium and S. bovis. Through a transcriptomic approach, we measured gene expression in both parental species and hybrids. We described and quantified expression profiles encountered in hybrids along with the main biological processes impacted. Up to 7,100 genes fell into a particular hybrid expression profile (intermediate between the parental expression levels, over-expressed, under-expressed, or expressed like one of the parental lines). Most of these genes were different depending on the direction of the parental cross (S. bovis mother and S. haematobium father or the reverse) and depending on the sex. For a given sex and cross direction, the vast majority of genes were hence unassigned to a hybrid expression profile: either they were differentially expressed genes but not typical of any hybrid expression profiles or they were not differentially expressed neither between hybrids and parental lines nor between parental lines. The most prevalent profile of gene expression in hybrids was the intermediate one (24% of investigated genes). These results suggest that transcriptomic compatibility between S. haematobium and S. bovis remains quite high. We also found support for an over-dominance model (over- and under-expressed genes in hybrids compared to parental lines) potentially associated with heterosis. In females in particular, processes such as reproductive processes, metabolism and cell interactions as well as signaling pathways were indeed affected. Our study hence provides new insight on the biology of Schistosoma hybrids with evidences supporting compatibility and heterosis.
Sujet(s)
Vigueur hybride , Hybridation génétique , Schistosoma haematobium , Schistosoma , Animaux , Vigueur hybride/génétique , Schistosoma haematobium/génétique , Femelle , Mâle , Schistosoma/génétique , Transcriptome , Analyse de profil d'expression de gènesRÉSUMÉ
Vitis amurensis grape, an East Asian Vitis species, has excellent cold and disease resistance and exhibits high winemaking potential. In this study, the aroma compounds in grapes from five V. amurensis cultivars ('Beiguohong', 'Beiguolan', 'Shuangfeng', 'Shuanghong', 'Shuangyou') and three interspecific hybrids ('Beibinghong', 'Xuelanhong', 'Zuoyouhong') from two regions (Zuojia and Ji'an, Jilin, China) were identified via HS-SPME-GC/MS. The results showed that V. amurensis grapes had a greater concentration of aroma compounds than the interspecific hybrid berries. 'Beibinghong' was relatively rich in terpenes, although their concentrations were all lower than the threshold. 'Shuangfeng' contained more concentrations of free C6/C9 compounds, alcohols, aromatics and aldehydes/ketones than the other cultivars. The aroma characteristics of 'Beiguolan' and 'Shuanghong' were relatively similar. The grapes from the lower temperature and more fertile soil of Zuojia contained more C6/C9 compounds, norisoprenoids and alcohols, while aromatics were more abundant in the grapes from Ji'an, which was warmer than the Zuojia region. Herbaceous, floral, fruity and sweet were the main aroma series of V. amurensis grapes. Our study could provide a reference for the development and utilization of V. amurensis grapes and lay a foundation for the development of wild grape cultivars and the production of wines with characteristic styles.
Sujet(s)
Fruit , Chromatographie gazeuse-spectrométrie de masse , Génotype , Odorisants , Vitis , Composés organiques volatils , Vin , Vitis/composition chimique , Vitis/génétique , Vitis/classification , Odorisants/analyse , Composés organiques volatils/analyse , Fruit/composition chimique , Vin/analyse , Chine , Hybridation génétique , Microextraction en phase solideRÉSUMÉ
The last couple of decades have highlighted the importance of studying hybridization, particularly among primate species, as it allows us to better understand our own evolutionary trajectory. Here, we report on genetic ancestry estimates using dense, full genome data from 881 olive (Papio anubus), yellow (Papio cynocephalus), or olive-yellow crossed captive baboons from the Southwest National Primate Research Center. We calculated global and local ancestry information, imputed low coverage genomes (n = 830) to improve marker quality, and updated the genetic resources of baboons available to assist future studies. We found evidence of historical admixture in some putatively purebred animals and identified errors within the Southwest National Primate Research Center pedigree. We also compared the outputs between two different phasing and imputation pipelines along with two different global ancestry estimation software. There was good agreement between the global ancestry estimation software, with R2 > 0.88, while evidence of phase switch errors increased depending on what phasing and imputation pipeline was used. We also generated updated genetic maps and created a concise set of ancestry informative markers (n = 1,747) to accurately obtain global ancestry estimates.