Assessment of genetic diversity in chinese hulless barley accessions for qualitative traits

Cultivated barley (Hordeum vulgare L.) has been proven to be an economically important model plant and having large genetic diversity among the species. The effective exploitation of qualitative characters in barley can be measured by its genetic diversity and interrelationship. This study aims to determine the assessment of genetic diversity in Chinese hulless barley accessions for qualitative traits. Presently, in this study, the genetic diversity of 208 Chinese hulless barley from different Provinces of China, 111 genotypes were from the Tibet plateau, 30 Sichuan, 2 USA, 1 Canada, 12 Gansu, 51 Qinghai, 1 Yunnan was investigated; collected. Almost all the qualitative traits including crude protein, fiber, starch, neutral detergent fiber, and acid detergent fiber exhibited significantly high variability (p≤0.0001) among the cultivars. The data were analyzed using Statistics 8.1. In this study, significantly high variation was observed between starch content and neutral detergent fiber (23.64% and 11.54%). However, the highest diversity is based on the magnitude of the coefficient of variation exhibited in crude protein (13.82%), starch (12.87%), and fiber (12.17%). There was a significantly positive correlation between fiber, acid detergent fiber, and neutral detergent fiber except for starch content with crude protein and fiber that exhibited a significant negative correlation (r= -0.38*** and r= -0.92***). A large genetic diversity was observed through cluster analysis among all the 208 barley accessions, distance coefficient ranging between 0.28 and 75.86. The histogram revealed that frequency distributions of 208 different genotypes of hulless barley crop with all five different characters, crude protein, fiber, starch, neutral detergent fiber, and acid detergent fiber, showed normal distribution. It is concluded that this hulless barley study showed genetic diversity among the accessions and confirmed genetic diversity in various traits used.

Genomic variations and distinct evolutionary rate of rare alleles in Arabidopsis thaliana.

BACKGROUND: The variation rate in genomic regions associated with different alleles, impacts to distinct evolutionary patterns involving rare alleles. The rare alleles bias towards genome-wide association studies (GWASs), aim to detect different variants at genomic loci associated with single-nucleotide polymorphisms (SNPs) inclined to produce different haplotypes. Here, we sequenced Arabidopsis thaliana and compared its coding and non-coding genomic regions with its closest outgroup relative, Arabidopsis lyrta, which accounted for the ancestral misinference. The use of genome-wide SNPs interpret the genetic architecture of rare alleles in Arabidopsis thaliana, elucidating a significant departure from a neutral evolutionary model and the pattern of polymorphisms around a selected locus will exclusively influence natural selection. RESULTS: We found 23.4% of the rare alleles existing randomly in the genome. Notably, in our results significant differences (P < 0.01) were estimated in the relative rates between rare versus intermediate alleles, between fixed versus non-fixed mutations, and between type I versus type II rare-mutations by using the χ (2)-test. However, the rare alleles generating negative values of Tajima's D suggest that they generated under selective sweeps. Relative to polymorphic sites including SNPs, 67.5% of the fixed mutations were attributed, indicating major contributors to speciation. Substantially, an evolution occurred in the rare allele that was 1.42-times faster than that in a major haplotype. CONCLUSION: Our results interpret that rare alleles fits a random occurrence model, indicating that rare alleles occur at any locus in a genome and in any accession in a species. Based on the higher relative rate of derived to ancient mutations and higher average D xy, we conclude that rare alleles evolve faster than the higher frequency alleles. The rapid evolution of rare alleles indicates that they must have been newly generated with fixed mutations, compared with the other alleles. Eventually, PCR and sequencing results, in the flanking regions of rare allele loci confirm that they are of short extension, indicating the absence of a genome-wide pattern for a rare haplotype. The indel-associated model for rare alleles assumes that indel-associated mutations only occur in an indel heterozygote.

Recent duplications drive rapid diversification of trypsin genes in 12 Drosophila.

Trypsin participates in many fundamental biological processes, the most notably in digesting food. The 12 species of Drosophila provide a great opportunity to analyze the duplication pattern of trypsins and their association with dietary changes. Here, we find that the trypsin family expands dramatically after speciation. The duplication events are strongly related to the host preferences, with significantly more copy numbers in species breeding on rotting fruits. Temporal analysis of the duplication events indicates that the occurrences of these events are not simultaneous, but rather correlate to the ecological change or host shift. Furthermore, we find that the specialists and generalists have different adaptive selections, which is revealed by dynamic duplication and/or deletion and relatively high Ka/Ks values on the duplicated events in specialists. Our findings suggest that the duplication of trypsin genes has played an important role in the adaption of Drosophila to the diverse ecosystems.