Genetic Polymorphism in Evolving Population

We present a model for evolving population which maintains genetic polymorphism. By introducing random mutation in the model population at a constant rate, we observe that the population does not become extinct but survives, keeping diversity in the gene pool under abrupt environmental changes. The model provides reasonable estimates for the proportions of polymorphic and heterozygous loci and for the mutation rate, as observed in nature

Blood ties: ABO is a trans-species polymorphism in primates

The ABO histo-blood group, the critical determinant of transfusion incompatibility, was the first genetic polymorphism discovered in humans. Remarkably, ABO antigens are also polymorphic in many other primates, with the same two amino acid changes responsible for A and B specificity in all species sequenced to date. Whether this recurrence of A and B antigens is the result of an ancient polymorphism maintained across species or due to numerous, more recent instances of convergent evolution has been debated for decades, with a current consensus in support of convergent evolution. We show instead that genetic variation data in humans and gibbons as well as in Old World Monkeys are inconsistent with a model of convergent evolution and support the hypothesis of an ancient, multi-allelic polymorphism of which some alleles are shared by descent among species. These results demonstrate that the ABO polymorphism is a trans-species polymorphism among distantly related species and has remained under balancing selection for tens of millions of years, to date, the only such example in Hominoids and Old World Monkeys outside of the Major Histocompatibility Complex.Comment: 45 pages, 4 Figures, 4 Supplementary Figures, 5 Supplementary Table

Infectivity and Genetic Polymorphism of Anopheles Maculatus and An. Vagus in Diverse Endemicity Malaria Areas in The Kokap Sub-District of Kulon Progo

BACKGROUND: It is crucial to regularly monitor the infectivity and genetic polymorphism of Anopheles sp in endemic areas for early detection and accurate rapid response planning of indigenous malaria transmission. The Kokap Sub-District has the highest number of malaria cases in the Kulon Progo District. Its five villages showed diverse malaria endemicities. Anopheles maculatus was pointed out as the main vector and An. vagus as a suspect vector. The purpose of this investigation was to examine whether the populations of these two species were different with regard to infectivity and genetic polymorphism in villages that were high endemic (HEV) and low endemic (LEV). SUBJECT AND METHODS: A cross-sectional observational study was performed in one HEV (Hargotirto) dan one LEV (Hargomulyo) on An. maculatus sp and An. vagus sp parous mosquitoes. The mosquitoes of both villages were collected simultaneously using the resting collection method, five times each, during October-December 2013. The collections were conducted in three houses by two collectors per house (one inside and one outside) in 50 minute intervels from 18.00PM to 06.00AM. Mosquitoes that meet the inclusion criteria were examined using the Multiplex-PCR method to detect the existence of Plasmodium and the Random Amplified Polymorphic DNA (RAPD) method to identify mosquito DNA polymorphism. RESULTS: The PCR test results of DNA samples of An. maculatus (25 HEV and 7 LEV) and An. vagus (18 HEV and 20 LEV) of the two villages showed that only the HEV sample was Plasmodium sp positive with 28% An. maculatus and 17% An. vagus infectivities (OR=6.08; CI95%: 0.31-120.4; p=0.043). The RAPD-PCR test results of DNA samples of An. maculatus (5 per village) and An. vagus (5 per village) of the two villages showed identical degrees of DNA polymorphism. CONCLUSION: The endemicity of the two villages was related to Anopheles sp infectivity. Although no Plasmodium sp positive anophelines were found in the LEV vector surveillance is nonetheless necessary considering the same levels of DNA polymorphism. Keywords: Anopheles sp, infectivity, endemicity, genetic polymorphis

Central role for the XRCC1 BRCT I domain in mammalian DNA single-strand break repair

The DNA single-strand break repair (SSBR) protein XRCC1 is required for genetic stability and for embryonic viability. XRCC1 possesses two BRCA1 carboxyl-terminal (BRCT) protein interaction domains, denoted BRCT I and II. BRCT II is required for SSBR during G1 but is dispensable for this process during S/G2 and consequently for cell survival following DNA alkylation. Little is known about BRCT I, but this domain has attracted considerable interest because it is the site of a genetic polymorphism that epidemiological studies have associated with altered cancer risk. We report that the BRCT I domain comprises the evolutionarily conserved core of XRCC1 and that this domain is required for efficient SSBR during both G1 and S/G2 cell cycle phases and for cell survival following treatment with methyl methanesulfonate. However, the naturally occurring human polymorphism in BRCT I supported XRCC1-dependent SSBR and cell survival after DNA alkylation equally well. We conclude that while the BRCT I domain is critical for XRCC1 to maintain genetic integrity and cell survival, the polymorphism does not impact significantly on this function and therefore is unlikely to impact significantly on susceptibility to cancer

A Novel Single Nucleotide Polymorphism in Exon 4 of Insulin-Like Growth Factor-1 Associated with Production Traits in Bali Cattle

Insulin-like growth factor-1 (IGF-1) is one of the gene candidates that can be used in selection strategy by using DNA markers (marker assisted selection). Gene candidate strategy is a molecular biology techniques to identify quantitative trait loci directly, with the assumption that genetic variation associated to quantitative trait variation. This study was designed to identify any new mutations in exon 4 that can cause the IGF-1 gene polymorphism and then affect the production traits on Bali cattle. Single nucleotide polymorphism (SNP) discovery was conducted by using the direct sequencing technique. Genetic variation of the genes candidate was identified by using PCR-RFLP technique. The results of this study indicate the presence of a new SNP in exon 4 of IGF-1 gene caused by the T/C transition, which can be identified using Rsa1 restriction enzyme. Genotypic polymorphism of IGF-1/Rsa1 has a significant influence on birth weight, weaning weight and average daily gain of Bali cattle. CC genotype had a birth weight rate, weaning weight and average daily gain of: 15.64±1.83; 83.15±9.00, and 0.439±0.07 respectively, higher than the TT and CT genotype. IGF-1/Rsa1 can be used as a genetic marker for selection of birth weight, weaning weight, and daily body weight gain

Life history and ecological genetics of the colonial ascidian Botryllus schlosseri

The colonial ascidian Botryllus schlosseri is a cosmopolitan, marine filter feeder, introduced as a laboratory research organism in the 1950s. Currently, it is widely used in many laboratories to investigate a variety of biological questions. Recently, it has become a species of concern, as it is an invasive species in many coastal environments. Here, we review studies on the geographical distribution of the species, sexual and asexual reproduction in the field, tolerance to temperature, salinity and anthropogenic activity, polychromatism, enzymatic polymorphism, and the genetic basis of pigmentation. Studying the relationship between genetic polymorphism and the adaptation of B. schlosseri to environmental stress is a challenge of future research and will improve our understanding of its evolutionary success and invasive potential

Mitochondrially-Encoded Adenosine Triphosphate Synthase 6 Gene Haplotype Variation Among World Population During 2003-2013

Background: Adaptation and natural selection serve as an important part of evolution. Adaptation in molecular level can lead to genetic drift which causes mutation of genetic material; one of which is polymorphism of mitochondrial DNA (mtDNA). The aim of this study is to verify the polymorphism of mitochondrially-encoded Adenosine Triphosphate synthase6gene (MT-ATP6) as one of mtDNA building blocks among tropic, sub-tropic, and polar areas. Methods: This descriptive quantitative research used 3,210 mtDNA sequences, taken from GenBank, as secondary data from 27 different populations. The data were grouped into 3 population groups based on the climates of their location. After grouping, the sequences were then aligned and trimmed using Unipro EUGENE, and analysed by Arlequin and MitoTool. Results: Results demonstrated 21 haplotypes distributed among 3 populations with variations between each climate population. In the tropic and sub-tropic populations, the dominant haplotype is h1 while h6 is dominant in the polar population. Conclusions: There is a variation of haplotype polymorphism between tropic, sub-tropic, and polar climate population. &nbsp

Aggregation of Single Nucleotide Polymorphisms in a Human H5N1 Clade 2.2 Hemagglutinin

The evolution of H5N1 has attracted significant interest 1-4 due to linkages with avian 5,6 and human infections 7,8. The basic tenets of influenza genetics 9 attribute genetic drift to replication errors caused by a polymerase complex that lacks a proof reading function. However, recent analysis 10 of swine influenza genes identifies regions copied with absolute fidelity for more than 25 years. In addition, polymorphism tracing of clade 2.2 H5N1 single nucleotide polymorphisms identify concurrent acquisition 11 of the same polymorphism onto multiple genetic backgrounds in widely dispersed geographical locations. Here we show the aggregation of regional clade 2.2 polymorphisms from Germany, Egypt, and sub-Sahara Africa onto a human Nigerian H5N1 hemagglutinin (HA), implicating recombination in the dispersal and aggregation of single nucleotide polymorphisms from closely related genomes

Long-term balancing selection drives evolution of immunity genes in Capsella.

Genetic drift is expected to remove polymorphism from populations over long periods of time, with the rate of polymorphism loss being accelerated when species experience strong reductions in population size. Adaptive forces that maintain genetic variation in populations, or balancing selection, might counteract this process. To understand the extent to which natural selection can drive the retention of genetic diversity, we document genomic variability after two parallel species-wide bottlenecks in the genus Capsella. We find that ancestral variation preferentially persists at immunity related loci, and that the same collection of alleles has been maintained in different lineages that have been separated for several million years. By reconstructing the evolution of the disease-related locus MLO2b, we find that divergence between ancient haplotypes can be obscured by referenced based re-sequencing methods, and that trans-specific alleles can encode substantially diverged protein sequences. Our data point to long-term balancing selection as an important factor shaping the genetics of immune systems in plants and as the predominant driver of genomic variability after a population bottleneck