Genome-wide sequence divergence of satellite DNA could underlie meiotic failure in male hybrids of bighead catfish and North African catfish (Clarias, Clariidae).

Hybrid sterility, a hallmark of postzygotic isolation, arises from parental genome divergence disrupting meiosis. While chromosomal incompatibility is often implicated, the underlying mechanisms remain unclear. This study investigated meiotic behavior and genome-wide divergence in bighead catfish (C. macrocephalus), North African catfish (C. gariepinus), and their sterile male hybrids (important in aquaculture). Repetitive DNA analysis using bioinformatics and cytogenetics revealed significant divergence in satellite DNA (satDNA) families between parental species. Notably, one hybrid exhibited successful meiosis and spermatozoa production, suggesting potential variation in sterility expression. Our findings suggest that genome-wide satDNA divergence, rather than chromosome number differences, likely contributes to meiotic failure and male sterility in these catfish hybrids.

Longitudinal study of age-specific pattern of coronavirus infection in Lyle's flying fox (Pteropus lylei) in Thailand.

BACKGROUND: Bats are natural reservoirs for several highly pathogenic and novel viruses including coronaviruses (CoVs) (mainly Alphacoronavirus and Betacoronavirus). Lyle's flying fox (Pteropus lylei)'s roosts and foraging sites are usually in the proximity to humans and animals. Knowledge about age-specific pattern of CoV infection in P. lylei, prevalence, and viral shedding at roosts and foraging sites may have an impact on infection-age-structure model to control CoV outbreak. METHODS: P. lylei bats were captured monthly during January-December 2012 for detection of CoV at three areas in Chonburi province; two human dwellings, S1 and S2, where few fruit trees were located with an open pig farm, 0.6 km and 5.5 km away from the bat roost, S3. Nested RT-PCR of RNA-dependent RNA polymerase (RdRp) gene from rectal swabs was used for CoV detection. The strain of CoV was confirmed by sequencing and phylogenetic analysis. RESULTS: CoV infection was found in both juveniles and adult bats between May and October (January, in adults only and April, in juveniles only). Of total rectal swab positives (68/367, 18.5%), ratio was higher in bats captured at S1 (11/44, 25.0%) and S2 (35/99, 35.4%) foraging sites than at roost (S3) (22/224, 9.8%). Juveniles (forearm length ≤ 136 mm) were found with more CoV infection than adults at all three sites; S1 (9/24, 37.5% vs 2/20, 10%), S2 (22/49, 44.9% vs 13/50, 26.0%), and S3 (10/30, 33.3% vs 12/194, 6.2%). The average BCI of CoV infected bats was significantly lower than uninfected bats. No gender difference related to infection was found at the sites. Phylogenetic analysis of conserved RdRp gene revealed that the detected CoVs belonged to group D betacoronavirus (n = 64) and alphacoronavirus (n = 4). CONCLUSIONS: The fact that CoV infection and shedding was found in more juvenile than adult bats may suggest transmission from mother during peripartum period. Whether viral reactivation during parturition period or stress is responsible in maintaining transmission in the bat colony needs to be explored.

Samae Dam Chicken: A variety of the Pradu Hang Dam breed revealed from microsatellite genotyping data.

Objective: The remarkable adaptability to the environment, high growth rate, meat with good taste and aroma, and ornamental appearance of the Pradu Hang Dam (PDH) and Samae Dam (SD) chickens make them valuable for improvement of poultry production to enhance food security. However, despite their close phenotypic similarity, distinct classification of PDH and SD chickens remains controversial. Thus, this study aimed to clarify genetic origins and variation between PDH and SD chickens, genetic diversity and structures of PDH and SD chickens. Methods: This study analyzed 5 populations of PDH and 2 populations of SD chickens using 28 microsatellite markers and compared with those of other indigenous and local chicken breeds using Thailand's "The Siam Chicken Bioresource Project" database. Results: Considerably high genetic variability was observed within PDH (370 total alleles; 4.086 ± 0.312 alleles/locus) and SD chickens (179 total alleles; 3.607 ± 0.349 alleles/locus). A partial overlap of gene pools was observed between SD chickens from the Department of Livestock, Uthai Thani (SD1) and PDH chickens, suggesting a potentially close relationship between the two chicken breeds. A gene pool that is partially overlapped with that of the red junglefowl was observed in the SD chicken population from the Sanhawat Farm Uthai Thani population (SD2). Distinct subclusters were observed within SD chickens, indicating the possibility that genetic differentiation occurred early in the process of establishment of SD chickens. Conclusion: These findings could offer valuable insights into genetic verification of Thai local chicken breeds and their sustainable conservation and utilization.

Weak purifying selection in allelic diversity of the ADSL gene in indigenous and local chicken breeds and red junglefowl in Thailand.

High levels of purine and uric acid, which are associated with health issues such as gout and cardiovascular disease, are found in the meat of fast-growing broiler chickens, which raises concerns about the quality of chicken meat and the health of the consumers who consume it. High genetic homogeneity and uniformity, particularly in genes involved in the synthesis of inosine monophosphate (IMP) and subsequent process of purine synthesis, which are associated with the meat quality, are exhibited in commercial broiler chickens owing to intensive inbreeding programs. Adenosine succinate lyase (ADSL) is a key enzyme involved in de novo purine biosynthetic pathway and its genetic polymorphisms affect IMP metabolism and purine content. In this study, we investigated the polymorphism of the ADSL gene in indigenous and local chicken breeds and red junglefowl in Thailand, using metabarcoding and genetic diversity analyses. Five alleles with 73 single nucleotide polymorphisms in exon 2, including missense and silent mutations, which may act on the synthesis efficiency of IMP and purine. Their protein structures revealed changes in amino acid composition that may affect ADSL enzyme activity. Weak purifying selection in these ADSL alleles was observed in the chicken population studied, implying that the variants have minor fitness impacts and a greater probability of fixation of beneficial mutations than strong purifying selection. A potential selective sweep was observed in Mae Hong Son chickens, whose purine content was lower than that in other breeds. This suggests a potential correlation between variations of the ADSL gene and reduced purine content and an impact of ADSL expression on the quality of chicken meat. However, further studies are required to validate its potential availability as a genetic marker for selecting useful traits that are beneficial to human health and well-being.

Research Note: Possible influence of thermal selection on patterns of HSP70 and HSP90 gene polymorphisms in Thai indigenous and local chicken breeds and red junglefowls.

The thermal stress caused by global climate change adversely affects the welfare, productivity, and reproductive performance of farm animals, including chickens, and causes substantial economic losses. However, the understanding of the genetic basis of the indigenous chicken adaptation to high ambient temperatures is limited. Hence, to reveal the genetic basis of thermal stress adaptation in chickens, this study investigated polymorphisms in the heat shock protein 70 (HSP70) and HSP90 genes, known mechanisms of cellular defense against thermal stress in indigenous and local chicken breeds and red junglefowls in Thailand. The result revealed seven alleles of the HSP70 gene. One allele exhibited a missense mutation, where an amino acid changed from Asn to His in the substrate-binding and peptide-binding domains, which is exclusive to the Lao Pa Koi chicken breed. Twenty new alleles with silent mutations in the HSP90 gene highlighted its greater complexity. Despite this diversity, distinct population structures were not found for either HSP70 or HSP90, which suggests incomplete impact on the domestication process and selection. The low genetic diversity, shown by the sharing of alleles between red junglefowls and Thai indigenous and local chicken breeds, aligns with the hypothesis that these alleles have undergone selection in tropical regions, such as Thailand. Selection signature analysis suggests the purifying selection of HSP70 for thermotolerance. This study provides valuable insights for enhancing the conservation of genetic resources with thermotolerant traits, which are essential for developing breeding programs to increase poultry production in the context of global climate change.

Questioning inbreeding: Could outbreeding affect productivity in the North African catfish in Thailand?

The North African catfish (Clarias gariepinus) is a significant species in aquaculture, which is crucial for ensuring food and nutrition security. Their high adaptability to diverse environments has led to an increase in the number of farms that are available for their production. However, long-term closed breeding adversely affects their reproductive performance, leading to a decrease in production efficiency. This is possibly caused by inbreeding depression. To investigate the root cause of this issue, the genetic diversity of captive North African catfish populations was assessed in this study. Microsatellite genotyping and mitochondrial DNA D-loop sequencing were applied to 136 catfish specimens, collected from three populations captured for breeding in Thailand. Interestingly, extremely low inbreeding coefficients were obtained within each population, and distinct genetic diversity was observed among the three populations, indicating that their genetic origins are markedly different. This suggests that outbreeding depression by genetic admixture among currently captured populations of different origins may account for the low productivity of the North African catfish in Thailand. Genetic improvement of the North African catfish populations is required by introducing new populations whose origins are clearly known. This strategy should be systematically integrated into breeding programs to establish an ideal founder stock for selective breeding.

Optimizing Microsatellite Marker Panels for Genetic Diversity and Population Genetic Studies: An Ant Colony Algorithm Approach with Polymorphic Information Content.

Microsatellites are polymorphic and cost-effective. Optimizing reduced microsatellite panels using heuristic algorithms eases budget constraints in genetic diversity and population genetic assessments. Microsatellite marker efficiency is strongly associated with its polymorphism and is quantified as the polymorphic information content (PIC). Nevertheless, marker selection cannot rely solely on PIC. In this study, the ant colony optimization (ACO) algorithm, a widely recognized optimization method, was adopted to create an enhanced selection scheme for refining microsatellite marker panels, called the PIC-ACO selection scheme. The algorithm was fine-tuned and validated using extensive datasets of chicken (Gallus gallus) and Chinese gorals (Naemorhedus griseus) from our previous studies. In contrast to basic optimization algorithms that stochastically initialize potential outputs, our selection algorithm utilizes the PIC values of markers to prime the ACO process. This increases the global solution discovery speed while reducing the likelihood of becoming trapped in local solutions. This process facilitated the acquisition of a cost-efficient and optimized microsatellite marker panel for studying genetic diversity and population genetic datasets. The established microsatellite efficiency metrics such as PIC, allele richness, and heterozygosity were correlated with the actual effectiveness of the microsatellite marker panel. This approach could substantially reduce budgetary barriers to population genetic assessments, breeding, and conservation programs.

Genetic admixture and diversity in Thai domestic chickens revealed through analysis of Lao Pa Koi fighting cocks.

Lao Pa Koi (LPK) chicken is a popular fighting breed in Thailand, prized for (its unique characteristics acquired by selective breeding), and a valuable model for exploring the genetic diversity and admixture of red junglefowls and domestic chickens. In this study, genetic structure and diversity of LPK chicken were assessed using 28 microsatellite markers and mitochondrial DNA (mtDNA) D-loop sequences, and the findings were compared to a gene pool library from "The Siam Chicken Bioresource Project". High genetic variability was observed in LPK chickens using mtDNA D-loop haplotype analysis, and six haplotypes were identified. Microsatellite data revealed 182 alleles, with an average of 6.5 alleles per locus. These results confirmed the occurrence of genetic admixture of red junglefowl and Thai domestic chickens in LPK chicken breed. A maximum entropy modeling approach was used to analyze the spatial suitability and to assess the adaptive evolution of LPK chickens in diverse local environments. The model identified 82.52% of the area studied as unsuitable, and 9.34%, 7.11%, and 2.02% of the area indicated moderate, low, and high suitability, respectively. The highest contribution rate to land suitability for LPK chickens was found at an elevation of 100-250 m, suggesting the importance of elevation for their potential distribution. The results of this study provide valuable insights into the genetic origin of LPK chicken breed and identify resources for future genetic improvement.

Environmental and Socio-Cultural Factors Impacting the Unique Gene Pool Pattern of Mae Hong-Son Chicken.

Understanding the genetic diversity of domestic chicken breeds under the impact of socio-cultural and ecological dynamics is vital for the conservation of natural resources. Mae Hong Son chicken is a local breed of North Thai domestic chicken widely distributed in Mae Hong Son Province, Thailand; however, its genetic characterization, origin, and diversity remain poorly understood. Here, we studied the socio-cultural, environmental, and genetic aspects of the Mae Hong Son chicken breed and investigated its diversity and allelic gene pool. We genotyped 28 microsatellite markers and analyzed mitochondrial D-loop sequencing data to evaluate genetic diversity and assessed spatial habitat suitability using maximum entropy modeling. Sequence diversity analysis revealed a total of 188 genotyped alleles, with overall nucleotide diversity of 0.014 ± 0.007, indicating that the Mae Hong Son chicken population is genetically highly diverse, with 35 (M1-M35) haplotypes clustered into haplogroups A, B, E, and F, mostly in the North ecotype. Allelic gene pool patterns showed a unique DNA fingerprint of the Mae Hong Son chicken, as compared to other breeds and red junglefowl. A genetic introgression of some parts of the gene pool of red junglefowl and other indigenous breeds was identified in the Mae Hong Son chicken, supporting the hypothesis of the origin of the Mae Hong Son chicken. During domestication in the past 200-300 years after the crossing of indigenous chickens and red junglefowl, the Mae Hong Son chicken has adapted to the highland environment and played a significant socio-cultural role in the Northern Thai community. The unique genetic fingerprint of the Mae Hong Son chicken, retaining a high level of genetic variability that includes a dynamic demographic and domestication history, as well as a range of ecological factors, might reshape the adaptation of this breed under selective pressure.

Overcoming taxonomic challenges in DNA barcoding for improvement of identification and preservation of clariid catfish species.

DNA barcoding without assessing reliability and validity causes taxonomic errors of species identification, which is responsible for disruptions of their conservation and aquaculture industry. Although DNA barcoding facilitates molecular identification and phylogenetic analysis of species, its availability in clariid catfish lineage remains uncertain. In this study, DNA barcoding was developed and validated for clariid catfish. 2,970 barcode sequences from mitochondrial cytochrome c oxidase I (COI) and cytochrome b (Cytb) genes and D-loop sequences were analyzed for 37 clariid catfish species. The highest intraspecific nearest neighbor distances were 85.47%, 98.03%, and 89.10% for COI, Cytb, and D-loop sequences, respectively. This suggests that the Cytb gene is the most appropriate for identifying clariid catfish and can serve as a standard region for DNA barcoding. A positive barcoding gap between interspecific and intraspecific sequence divergence was observed in the Cytb dataset but not in the COI and D-loop datasets. Intraspecific variation was typically less than 4.4%, whereas interspecific variation was generally more than 66.9%. However, a species complex was detected in walking catfish and significant intraspecific sequence divergence was observed in North African catfish. These findings suggest the need to focus on developing a DNA barcoding system for classifying clariid catfish properly and to validate its efficacy for a wider range of clariid catfish. With an enriched database of multiple sequences from a target species and its genus, species identification can be more accurate and biodiversity assessment of the species can be facilitated.

Mapping Risk of Nipah Virus Transmission from Bats to Humans in Thailand.

Nipah virus (NiV) is a zoonotic virus that can pose a serious threat to human and livestock health. Old-world fruit bats (Pteropus spp.) are the natural reservoir hosts for NiV, and Pteropus lylei, Lyle's flying fox, is an important host of NiV in mainland Southeast Asia. NiV can be transmitted from bats to humans directly via bat-contaminated foods (i.e., date palm sap or fruit) or indirectly via livestock or other intermediate animal hosts. Here we construct risk maps for NiV spillover and transmission by combining ecological niche models for the P. lylei bat reservoir with other spatial data related to direct or indirect NiV transmission (livestock density, foodborne sources including fruit production, and human population). We predict the current and future (2050 and 2070) distribution of P. lylei across Thailand, Cambodia, and Vietnam. Our best-fit model predicted that central and western regions of Thailand and small areas in Cambodia are currently the most suitable habitats for P. lylei. However, due to climate change, the species range is predicted to expand to include lower northern, northeastern, eastern, and upper southern Thailand and almost all of Cambodia and lower southern Vietnam. This expansion will create additional risk areas for human infection from P. lylei in Thailand. Our combined predictive risk maps showed that central Thailand, inhabited by 2.3 million people, is considered highly suitable for the zoonotic transmission of NiV from P. lylei. These current and future NiV transmission risk maps can be used to prioritize sites for active virus surveillance and developing awareness and prevention programs to reduce the risk of NiV spillover and spread in Thailand.

Coincidence of low genetic diversity and increasing population size in wild gaur populations in the Khao Phaeng Ma Non-Hunting Area, Thailand: A challenge for conservation management under human-wildlife conflict.

The gaur (Bos gaurus) is found throughout mainland South and Southeast Asia but is listed as an endangered species in Thailand with a decreasing population size and a reduction in suitable habitat. While gaur have shown a population recovery from 35 to 300 individuals within 30 years in the Khao Phaeng Ma (KPM) Non-Hunting Area, this has caused conflict with villagers along the border of the protected area. At the same time, the ecotourism potential of watching gaurs has boosted the local economy. In this study, 13 mitochondrial displacement-loop sequence samples taken from gaur with GPS collars were analyzed. Three haplotypes identified in the population were defined by only two parsimony informative sites (from 9 mutational steps of nucleotide difference). One haplotype was shared among eleven individuals located in different subpopulations/herds, suggesting very low genetic diversity with few maternal lineages in the founder population. Based on the current small number of sequences, neutrality and demographic expansion test results also showed that the population was likely to contract in the near future. These findings provide insight into the genetic diversity and demography of the wild gaur population in the KPM protected area that can inform long-term sustainable management action plans.