RESUMO
Tigers and their close relatives (Panthera) are some of the world's most endangered species. Here we report the de novo assembly of an Amur tiger whole-genome sequence as well as the genomic sequences of a white Bengal tiger, African lion, white African lion and snow leopard. Through comparative genetic analyses of these genomes, we find genetic signatures that may reflect molecular adaptations consistent with the big cats' hypercarnivorous diet and muscle strength. We report a snow leopard-specific genetic determinant in EGLN1 (Met39>Lys39), which is likely to be associated with adaptation to high altitude. We also detect a TYR260G>A mutation likely responsible for the white lion coat colour. Tiger and cat genomes show similar repeat composition and an appreciably conserved synteny. Genomic data from the five big cats provide an invaluable resource for resolving easily identifiable phenotypes evident in very close, but distinct, species.
Assuntos
Genoma/genética , Leões/genética , Panthera/genética , Tigres/genética , Adaptação Fisiológica/genética , Sequência de Aminoácidos , Animais , Variação Genética , Dados de Sequência Molecular , Mutação/genética , Densidade Demográfica , Sintenia/genéticaRESUMO
The Tibetan antelope (Pantholops hodgsonii) is endemic to the extremely inhospitable high-altitude environment of the Qinghai-Tibetan Plateau, a region that has a low partial pressure of oxygen and high ultraviolet radiation. Here we generate a draft genome of this artiodactyl and use it to detect the potential genetic bases of highland adaptation. Compared with other plain-dwelling mammals, the genome of the Tibetan antelope shows signals of adaptive evolution and gene-family expansion in genes associated with energy metabolism and oxygen transmission. Both the highland American pika, and the Tibetan antelope have signals of positive selection for genes involved in DNA repair and the production of ATPase. Genes associated with hypoxia seem to have experienced convergent evolution. Thus, our study suggests that common genetic mechanisms might have been utilized to enable high-altitude adaptation.
Assuntos
Antílopes/genética , Genoma/genética , Adaptação Fisiológica/genética , Altitude , Animais , Sequência de Bases , Evolução Molecular , Ontologia Genética , Heterozigoto , Dados de Sequência Molecular , Família Multigênica/genética , Polimorfismo de Nucleotídeo Único/genética , Seleção Genética , Análise de Sequência de DNA , Tibet , Ursidae/genéticaRESUMO
BACKGROUND: The mechanism of high-altitude adaptation has been studied in certain mammals. However, in avian species like the ground tit Pseudopodoces humilis, the adaptation mechanism remains unclear. The phylogeny of the ground tit is also controversial. RESULTS: Using next generation sequencing technology, we generated and assembled a draft genome sequence of the ground tit. The assembly contained 1.04 Gb of sequence that covered 95.4% of the whole genome and had higher N50 values, at the level of both scaffolds and contigs, than other sequenced avian genomes. About 1.7 million SNPs were detected, 16,998 protein-coding genes were predicted and 7% of the genome was identified as repeat sequences. Comparisons between the ground tit genome and other avian genomes revealed a conserved genome structure and confirmed the phylogeny of ground tit as not belonging to the Corvidae family. Gene family expansion and positively selected gene analysis revealed genes that were related to cardiac function. Our findings contribute to our understanding of the adaptation of this species to extreme environmental living conditions. CONCLUSIONS: Our data and analysis contribute to the study of avian evolutionary history and provide new insights into the adaptation mechanisms to extreme conditions in animals.
Assuntos
Adaptação Fisiológica/genética , Altitude , Genoma/genética , Passeriformes/genética , Animais , Sequência de Bases , Evolução Molecular , Anotação de Sequência Molecular , Fases de Leitura Aberta/genética , Filogenia , Seleção Genética , Análise de Sequência de DNA , Especificidade da Espécie , Sintenia/genéticaRESUMO
High-throughput sequencing is a revolutionary technological innovation in DNA sequencing. This technology has an ultra-low cost per base of sequencing and an overwhelmingly high data output. High-throughput sequencing has brought novel research methods and solutions to the research fields of genomics and post-genomics. Furthermore, this technology is leading to a new molecular breeding revolution that has landmark significance for scientific research and enables us to launch multi-level, multi-faceted, and multi-extent studies in the fields of crop genetics, genomics, and crop breeding. In this paper, we review progress in the application of high-throughput sequencing technologies to plant molecular breeding studies.
Assuntos
Produtos Agrícolas/genética , Embaralhamento de DNA/tendências , Análise de Sequência de DNA/tendências , Variação Genética , Genoma de Planta , Mutação , Locos de Características QuantitativasRESUMO
A soybean MADS box gene GmGAL2 (Glycine max AGAMOUS Like 2), a homolog of AGL11/STK, was investigated in transgenic Arabidopsis lines. Ectopic expression of GmGAL2 in Arabidopsis enhanced flowering, under both long-day and short-day conditions, by promoting expression of key flowering genes, CONSTANS (CO) and FLOWERING LOCUS T (FT), and lowering expression of floral inhibiter FLOWERING LOCUS C (FLC). Moreover, frequency of silique pod set was also lower in transgenic compared to control Arabidopsis plants. RT-PCR results revealed that GmGAL2 was primarily expressed in the flowers and pods of soybean plants, GmGAL2 expressed higher in SD than LD in soybean.
RESUMO
Soybean is a typical short-day crop, and its photoperiodic response of flowering is critical to its yield. This phenomenon was well studied during the last century, but the molecular mechanism governing it is unknown. The clock-gene homologs, GmLCL1 and GmLCL2 (Glycine max LHY/CCA1 Like 1 and 2) and GmTOC1 (Glycine max TOC1) were cloned from Glycine max L. KN18, and their expression patterns were analyzed using a system developed in this study. We employed 8h light/16h dark and 18h light/6h dark as short- and long-day conditions, respectively, because in these conditions soybean plants had significant indexes of flowering time. We also used unifoliolates, not the whole plant as Arabidopsis, as target organs for gene expression analysis. GmLCL1 and GmLCL2 had similar circadian expression patterns and both were morning genes, while GmTOC1 was an evening gene and peaked in the evening. The expressions of GmLCL1 and GmLCL2 were obviously antiphase to that of GmTOC1.Our study provided a system that simplified the experiments without compromising the quality of data obtained and was suitable for analyzing the molecular mechanism of flowering in soybean. GmLCL1, GmLCL2 and GmTOC1 may be the components of central clock in soybean.
