Exploration Of Genetic Diversity Research Articles

Exploration of Genetic Variation and Population Structure in Bergenia ciliata for its Conservation Implications.

Bergenia ciliata (Haw.)Sternb. is a perennial medicinal herb distributed in Indian Himalayan Region(IHR). A total of eight populations of B.ciliata were collected from diverse locales of IHR, and 17 EST-SSR markers were used in this study. The present study revealed moderate genetic diversity at the locus level with the mean number of alleles (Na = 7.823), mean number effective of alleles (Ne = 3.375), mean expected heterozygosity (He = 0.570), and meanShannon's diversity index (I = 1.264). The MSR (He = 0.543, I = 1.067) and DRJ populations (He = 0.309, I = 0.519) revealed the highest and lowest genetic diversity at the population level, respectively. AMOVA analysis showed that 81.76% of genetic variation was within populations, 10.55% was among populations, and 7.69% was among the regions. In addition, a moderate to high level of differentiation was found among the populations (FST = 0.182), which could be indicative of low to moderate gene flow (Nm = 0.669) in the B. ciliata populations. UPGMA and PCoA analysis revealed that eight populations could be differentiated into two groups, while the structure analysis of the 96 individuals differentiated into three groups. The Mantel test showed a positive relationship between genetic and geographical distance. The findings of this study will provide the development of conservation and germplasm management strategies for this valuable medicinal species.

EP446 - Exploration of genetic variation beyond leukocyte-derived germline DNA in a pediatric rare disease cohort

eP446 - Exploration of genetic variation beyond leukocyte-derived germline DNA in a pediatric rare disease cohort

Genotyping complex structural variation at the malaria-associated human glycophorin locus using a PCR-based strategy.

Structural variation in the human genome can affect risk of disease. An example is a complex structural variant of the human glycophorin gene cluster, called DUP4, which is associated with a clinically significant level of protection against severe malaria. The human glycophorin gene cluster harbours at least 23 distinct structural variants, and accurate genotyping of this complex structural variation remains a challenge. Here, we use a polymerase chain reaction-based strategy to genotype structural variation at the human glycophorin gene cluster, including the alleles responsible for the U- blood group. We validate our approach, based on a triplex paralogue ratio test, on publically available samples from the 1000 Genomes project. We then genotype 574 individuals from a longitudinal birth cohort (Tori-Bossito cohort) using small amounts of DNA at low cost. Our approach readily identifies known deletions and duplications, and can potentially identify novel variants for further analysis. It will allow exploration of genetic variation at the glycophorin locus, and investigation of its relationship with malaria, in large sample sets at minimal cost, using standard molecular biology equipment.

Morphological and molecular evidence of population divergence in a widespread shorebird across its southern mainland Australian distribution

We characterize geographical variation in the genetics, ecology, morphology and plumage of the Hooded Plover Charadrius cucullatus, a threatened shorebird widespread on coasts (south-east) and saltlakes (south-west) across the southern mainland of Australia. We confirm the distinctness of populations on either side of the Nullabor Plain/Great Australian Bight indicating that this apparent biogeographic barrier to terrestrial flora and fauna also influenced the phylogeographic pattern of a resident shorebird which is dependent on access to saline/hypersaline water. Western birds are genetically distinct, larger and have darker plumage than those in the east. Distinct ecological differences also exist, with eastern birds being resident, usually occurring on ocean beaches, with generalised diets and seasonal, solitary breeding. Western birds are nomadic, breeding when suitable conditions prevail, and exhibit more specialized diets, and may at times breed semi-colonially. Within the extensive eastern population, genetic analyses revealed an isolation by distance pattern, as well as genetic evidence of a long distance dispersal event. South Australian birds are distinct from Victorian birds, but cluster closely with Victorian birds in all genetic analyses. The western population features little genetic structuring, consistent with nomadism and congregatory behavior associated with drought/flood events. The distinctness of western populations found using multiple lines of evidence and the lack of evidence for any recent migration events across the Nullabor Plain, suggests that previously described subspecies warrant reinstatement, and that these evolutionary units require conservation assessment, as has been recognized by national conservation authorities. Conservation management of the eastern population should occur across its distribution, taking care to capture the genetic variability which is evident within this population. Further exploration of genetic variation between Eastern states is suggested.

Genetic variations of HvP5CS1 and their association with drought tolerance related traits in barley (Hordeum vulgare L.)

Delta-1-pyrroline-5-carboxylate synthase gene1 (P5CS1) is the key gene involved in the biosynthesis of proline and is significantly induced by drought stress. The exploration of genetic variation in HvP5CS1 may facilitate a better understanding of the mechanism of drought adaptation in barley. In the current study, 41 polymorphisms including 16 single nucleotide polymorphisms (SNPs) and 25 insertions/deletions (indels) were detected in HvP5CS1 among 287 barley (Hordeum vulgare L.) accessions collected worldwide, with 13 distinct haplotypes identified in the barley collection. Five polymorphisms in HvP5CS1 were significantly (P < 0.001) associated with drought tolerance related traits in barley. The phenotypic variation of a given trait explained by each associated polymorphism ranged from 4.43% to 9.81%. Two sequence variations that were significantly (P < 0.0001) associated with grain yield had marginally significant positive Tajima’s D values in the sliding window, so they might have been selected for environmental adaptation. Meanwhile, two haplotypes HvP5CS1_H1 and HvP5CS1_H4, which contained desired alleles of the two variations mentioned above, were significantly (P < 0.001) associated with drought tolerance related traits, and explained 5.00~11.89% of the phenotypic variations. These variations associated with drought tolerance related traits can be used as potential markers for improving drought tolerance in barley.

Combining bulk segregation analysis and microarrays for mapping of the pH trait in melon

The availability of sequence information for many plants has opened the way to advanced genetic analysis in many non-model plants. Nevertheless, exploration of genetic variation on a large scale and its use as a tool for the identification of traits of interest are still rare. In this study, we combined a bulk segregation approach with our own-designed microarrays to map the pH locus that influences fruit pH in melon. Using these technologies, we identified a set of markers that are genetically linked to the pH trait. Further analysis using a set of melon cultivars demonstrated that some of these markers are tightly linked to the pH trait throughout our germplasm collection. These results validate the utility of combining microarray technology with a bulk segregation approach in mapping traits of interest in non-model plants.

New insight in the pathogenesis of functional gastrointestinal disorders: association between genetics and colonic transit

Genome wide association studies and meta-analyses identified risk factors related to epithelial integrity of the intestinal barrier, innate immune responses and autophagy in inflammatory bowel disorder (IBD) and celiac disease. Irritable bowel syndrome (IBS), the most common functional gastrointestinal disorder (FGID), coexists and shares common, although milder, features with IBD and celiac disease. Although our knowledge on genetic variability in IBS symptom generation is very limited, smaller scale studies attempt to provide insight in the mechanisms underlying IBS. Camilleri etal. identified associations for susceptibility loci in inflammatory and epithelial barrier genes with colonic transit in lower FGID. Their report is the first descriptive study to assess potential genetic factors involved in motor function. Further exploration of genetic variation in IBS will be crucial to unravel its' pathogenesis.

Identification of a Cardiac Disease Modifier Gene Using Forward Genetics in the Mouse

Identification of a Cardiac Disease Modifier Gene Using Forward Genetics in the Mouse