Hardy-Weinberg Expectations Research Articles

Genetic consequences of social structure in the golden-crowned sifaka

Many species are structured in social groups (SGs) where individuals exhibit complex mating strategies. Yet, most population genetic studies ignore SGs either treating them as small random-mating units or focusing on a higher hierarchical level (the population). Empirical studies acknowledging SGs have found an overall excess of heterozygotes within SGs and usually invoke inbreeding avoidance strategies to explain this finding. However, there is a lack of null models against which ecological theories can be tested and inbreeding avoidance quantified. Here, we investigate inbreeding (deviation from random mating) in an endangered forest-dwelling pair-living lemur species (Propithecus tattersalli). In particular, we measure the inbreeding coefficient (FIS) in empirical data at different scales: SGs, sampling sites and forest patches. We observe high excess of heterozygotes within SGs. The magnitude of this excess is highly dependent on the sampling scheme: while offspring are characterised by a high excess of heterozygotes (FIS < 0), the reproductive pair does not show dramatic departures from Hardy–Weinberg expectations. Moreover, the heterozygosity excess disappears at larger geographic scales (sites and forests). We use a modelling framework that incorporates details of the sifaka mating system but does not include active inbreeding avoidance mechanisms. The simulated data show that, although apparent “random mating” or even inbreeding may occur at the “population” level, outbreeding is maintained within SGs. Altogether our results suggest that social structure leads to high levels of outbreeding without the need for active inbreeding avoidance mechanisms. Thus, demonstrating and measuring the existence of active inbreeding avoidance mechanisms may be more difficult than usually assumed.

Polymorphism of HLA-A, -B, -C, -DRB1 and -DQB1 Allele and Haplotype Frequency at High Resolution in Guangxi Zhuang Population

To analyze the characteristics of allelic and haplotypic polymorphisms of human leukocyte antigens at HLA-A, -B, -C, DRB1 and DQB1 loci in Guangxi Zhuang population. Polymerase chain reaction-sequence based typing (PCR-SBT) was used to detect. The five loci (HLA-A, -B, -C, -DRB1, -DQB1) in 350 unrelated Zhuang ethnic individual from Guangxi region. Allelic and haplotypic frequencies were calculated by using Arlequin software 3.5.2.2. Phylogeny tree were constructed by using MEGA software 6.0, and SPSS software was used for principal component analysis. Among the five loci in the population, only HLA-A and DRB1 loci were observed as departures from Hardy-Weinberg expectations. A total of 19 HLA-A, 42 HLA-B, 22 HLA-C, 25 HLA-DRB1 and 15 HLA-DQB1 alleles were found in 350 samples. The most highest frequent alleles were A*11: 01(28.57%), B*46: 01(14.00%), C*01: 02(18.43%), DRB1*16: 02 (15.71%）and DQB1*05: 02 (35.00%) . The most common five loci haplotype was A*33: 03-C*03: 02-B*58: 01-DRB1*03: 01-DQB1*02: 01（6.86%）. The phylogenetic tree analysis showed that Guangxi Zhuang population had a relative close genetic relationship with southern Han Chinese populations. This reaserch found that the HLA-A, B, C, DRB1 and DQB1 loci are highly polymorphic in Guangxi Zhuang population.

Microsatellite marker-based variation in the growth hormone genes of Nile tilapia (Oreochromis niloticus)

Polymorphisms in growth hormone genes have been found to cause variation in growth performance of fish. The objective of the study was to reveal variations in microsatellite loci located in the growth hormone genes of Nile tilapia (Oreochromis niloticus). Five microsatellite loci namely GH-MS01, IGFII, IGFII-MS01, IGFII-MS03, and STR were analyzed to assess the genetic variation in the growth hormone genes of four stocks of O. niloticus viz. FBG-Mini Hatchery, FM-Mini hatchery, Eon Aquaculture Ltd. and BFRI. The microsatellite markers were amplified by polymerase chain reaction, separated by polyacrylamide gel electrophoresis and visualized through ethidium bromide staining. All the five loci were found to be polymorphic. The average number of alleles of FM-Mini hatchery stock (3.8) was found to be highest and that of the FBG-Mini hatchery (2.8) and Eon Aquaculture stocks was found to be lowest. The average observed heterozygosity (Ho) value of the FM-Mini hatchery stock was the highest (0.140) and that of FBG-Mini hatchery stock was the lowest (0.040). On the other hand, the average expected heterozygosity (He) was highest in the BFRI stock (0.660) and lowest in the FM-Mini hatchery and FBG-Mini hatchery stock (0.432). The fixation index (1 - (Ho / He) values were positive in all the loci (except locus GH-MS01 in Eon Aquaculture stock), which means these stocks (O. niloticus) were deficient in heterozygosity. Deviation from Hardy-Weinberg expectation at STR locus in FBG-Mini hatchery and Eon Aquaculture stocks were not significant but in all other cases the deviations were found to be significant. The results provide evidence that genetic variation exists within the growth hormone genes in all four stocks of O. niloticus. The polymorphisms that have been detected in the present study can be used to study association with growth and thus selection of fast growing Nile tilapia in Bangladesh.

Kcnj11 Gene Polymorphism And Endurance Performance Status In Hispanics: A Replication Study

Previous reports from our laboratory had shown significant associations between the potassium inwardly-rectifying channel, subfamily J, member 11 (KCNJ11) gene Glu23Lys variant and cardiorespiratory endurance performance (CRE) phenotypes (Padró et al. (2003), MSSE, 35(S1), 377; González et al. (2003), MSSE 35(S1), 378; Ortiz et al. 2005, MSSE 37(S1), 165). The KCNJ11 gene, is expressed in several tissues, including cardiac and skeletal muscle, where it is involved in the coupling of cell metabolism to cell electrical activity. PURPOSE: To replicate the study Ortiz et al. 2005, MSSE 37(S1), 165) and validate the findings of Padró et al. (2003), MSSE, 35(S1), 377; González et al. (2003), MSSE 35(S1), 378, by testing the association between the KCNJ11 gene Glu23Lys variant and CRE performance level in Hispanic male marathon runners (MR) using a good-sized sample size. METHODS: The subjects (n=1778) were adult Hispanic male MR that completed a 42-km road race. Fast-MR (cases; n=884) were finishers in the top third percentile. Slow MR (controls; n=894) were finishers in the lowest third percentile of their respective ages. A whole blood sample provided for the extraction of genomic DNA. The polymerase chain reaction was used to amplify the KCNJ11 gene Glu23Lys variant. Both case and control groups observed genotype frequencies met Hardy-Weinberg equilibrium expectations (X2, P≥0.05). RESULTS: The main finding showed a statistically significant (p ≤0.05) association between the KCNJ11 gene Glu23Lys variant and CRE performance level. Fast-MR (cases) showed a significant over-representation of the KCNJ11 gene Glu23Lys variant compared to slow-MR (controls), 67.4% vs. 51.5%, (p ≤0.05). CONCLUSION: The study replicated and validated previous findings of an association between the KCNJ11 gene Glu23Lys variant and cardiorespiratory endurance.

Karyotype structure and polymorphism peculiarities of Chironomus nuditarsis Keyl, 1961 (Diptera, Chironomidae) from natural populations of North Caucasus.

The study presents data on the karyotype characteristics and features of chromosomal polymorphism of Chironomus nuditarsis Keyl, 1961 (Diptera, Chironomidae) from seven natural populations of Caucasus (Northwest, Central and East Caucasus). We found 16 banding sequences in the Caucasian populations. We observed inversion polymorphism almost in all chromosome arms except for arms C and E. The genetic distances between all the studied populations of Ch. nuditarsis were calculated using Nei criteria (1972). In spite of relative geographic proximity, the genetic distances between populations of the Caucasus are quite big, and they do not form a single cluster of Caucasian populations. The population of the Northwest Caucasus goes to European cluster; the populations of Central and East Caucasus form their own separate clusters. The principal component analysis (PCA) shows the similar picture. We suggest that such a clear separation of Caucasian populations in distinct clusters is a result of differences of collection sites in terms of geography and climate (complex diverse terrain and microclimate conditions). Four of the Caucasian populations do not follow Hardy-Weinberg expectation. In two populations, there being a marked deficiency of heterozygotes in arms B, F and G. In two other populations, there being a marked excess of heterozygotes in arms B and G. One can suggest that observed pictures could be a reflection of multi-directional selection of heterozygotes in different populations. The populations of Ch. nuditarsis from different parts of the Caucasus possibly diverged from each other at the level of subspecies. All the obtained data are indicative of the complex genetic structure of Caucasian populations of Ch. nuditarsis and total complexity of microevolution processes occurring in the Caucasus region.

Genetic polymorphisms of fecundity genes in Watish Sudanese desert sheep.

Background and Aim:The Watish sheep is a strain of desert sheep of smaller size compared to other desert sheep ecotypes, and there is anecdotal evidence that it is endowed with high litter size. The present study was designed for screening for polymorphisms in the known fecundity genes (bone morphogenetic protein receptor type 1B A<G in exon 6, bone morphogenetic protein 15 (BMP15) (FecXB, FecXG, FecXH, and FecXI) in exon2, growth differentiation factor 9 (GDF9) – G1 in exon1 and G8 in exon2 and PRLG<A in intron2) and their association with litter size in Watish.Materials and Methods:The study involved 156 Watish ewes of 2-6 years of age, along with data on litter size in the first, second, and third parity from Sinnar state and contiguous Blue Nile State. Genomic DNA was isolated and genotyped using polymerase chain reaction-restriction fragment length polymorphism. Allele and genotype frequencies were calculated by direct counting. Chi-square test for goodness of fit was performed for agreement with Hardy-Weinberg expectations and association testing.Results:The results demonstrated that all individuals were non-carriers for the target mutations of FecB, BMP15 (FecXB, FecXH, and FecXI), and GDF9-G8. With regard to the GDF9-G1 gene, the genotypic frequencies were 0.07% (G+) and 0.93% (++), in FecXG gene they were 0.993% (++) and 0.006% (B+), in PRL gene 0.516(++), 0.347(B+), and 0.137(BB). The Chi-square test showed a non-significant association between ewe’s type of birth and the detected mutations genotypes.Conclusion:These results preliminarily indicated that GDF9-G1, BMP15 (FecXG), and PRL genes might have had some contribution for improving litter size in Watish Sudanese sheep. However, further studies using larger samples are needed to detect the effects of those mutations on Watish sheep litter size.

&lt;p class="Body"&gt;&lt;strong&gt;Development and characterization of five microsatellite loci for the hard tick &lt;em&gt;Hyalomma marginatum&lt;/em&gt; (Acari: Ixodidae), through next generation sequencing&lt;/strong&gt;&lt;/p&gt;

Hyalomma marginatum is a hard tick species of medical and veterinary importance that is widely distributed throughout Turkey. In this study, five novel polymorphic microsatellite markers were isolated and developed from partial genome information using the Hiseq Illumina paired end technology. A total of 20,943,321 reads were obtained from vegetation collected specimens, 103 primer pairs were randomly selected for the analysis and 62 of them were tested for polymorphism. Seventy five specimens from nine different localities of Turkey were genotyped. Markers for selected loci were tested using labeled primers on capillary electrophoresis. Five loci were successfully scored and used to analyze genetic diversity. The number of alleles per locus ranged from 4 to 7, with an average of 5.4 alleles per locus. The average observed and expected heterozygosity values were 0.314 and 0.468, respectively. Two loci deviated significantly from Hardy-Weinberg expectations. No significant linkage disequilibrium was detected between loci. This study is the first attempt to generate genome sequence data and to develop SSR markers for H. marginatum. These markers will be useful to understand the taxonomic status of this vector, its population dynamics, and spatial distributions as well as mechanisms underlying Crimean Congo Heamorrhagic Fever transmission and the development and implementation of well-designed prevention strategies.

Forensic statistical parameters of 22 autosomal STRs in Mestizos from the Peninsula of Yucatán, México

The Mestizo (admixed) population of the Peninsula of Yucatan (Southeast, México) characterizes by a predominant Native American origin involving the Mayan culture. Autosomal Short tandem repeats (STRs) are the election tool for human identification (HID) purposes, such as forensic casework and paternity testing, among others. Although there are autosomal STR databases for some Mexican populations, the HID kits with more STRs have poorly studied in this country. Therefore, we estimated forensic parameters for 22 autosomal STRs belonging to the PowerPlex® Fusion System Promega kit (Promega, Corp.) in a population sample of 733 Mexican Mestizos subjects from the Peninsula of Yucatán (Southeast, Mexico). Buccal swabs were used as DNA sample for direct PCR multiplex amplification for genotyping PowerPlex® Fusion System Promega kit. Forensic parameters were obtained with Powerstats 1.2 software. Hardy-Weinberg expectations (HWE) were estimated with GDA ver 1.1 software. Gene diversity was estimated with Shannon-Wiener (H`) and statistical differences with t-test modified by Hutcheson using Biodiv 5.1 software. Interpopulation comparisons were analyzed with Dice and Rogers-Tanimoto indexes and classification method of Unweighted Pair-Group Method (UPGMA). Genotype distribution was in agreement with HWE (p > 0.001), except for D1S1656. FGA and Penta E were the most polymorphic loci with 32 and 25 different alleles, respectively. Heterozygosity ranged from 0.6112 for D22S1045 to 0.9141 for D1S1656. The most discriminating loci were Penta E (0.9852) and FGA (0.9756). The combined power of discrimination and combined power of exclusion were 1.9093 × 10−26 and 99.9999833%, respectively. Gene diversity ranged from 1.21 for D22S1045 to 2.68 for Penta E. Inter-comparison populations did not show significant differences for gene diversity based on allelic frequencies of 22 studied autosomal STR. Our results provide a STR population dataset that allow confident interpretation of paternity tests and criminal cases carried out with this HID system in the Peninsula of Yucatan.

Population genetics of 30 insertion-deletion polymorphism in polish Populations

The Investigator DIPplex® kit (Qiagen) contains components for the simultaneous amplification and analysis of 30 biallelic autosomal InDels and amelogenin. The objective of this study was to estimate the diversity of the 30 markers in a Polish population sample (N = 389) and to evaluate their usefulness in forensic genetics. The DIPplex genotype distributions showed no significant deviation from Hardy-Weinberg rule expectations (Bonferroni corrected). The mean observed heterozygosity value is 0.4611, and the combined Matching Probability value is 1.08x10−13. The investigated marker set has been confirmed as a potential extension to standard STR - based kits or a separate informative system for individual identification and kinship analysis.

Human leukocyte antigen-G polymorphisms in periodontitis

Objective: This study evaluated human leucocyte antigen-G gene polymorphisms in patients with periodontitis and healthy controls.Material and methods: The insertion/deletion polymorphism of 14 bp and a single nucleotide polymorphism (SNP) C > G on the position +3142 of the 3′ untranslated region of the gene were analyzed in chronic periodontitis (n = 62), aggressive periodontitis (n = 24) patients and healthy individuals (n = 47).Results: Considering the 14 bp insertion/deletion, a significant deviation from Hardy-Weinberg expectations in the chronic periodontitis group was observed, but not in the other groups. No significant deviations were observed in patients and control groups considering the +3142 C > G SNP. A significant increased frequency of homozygotes for the 14 bp deletion allele was observed in the chronic periodontitis group as compared to controls. This group also presented a higher frequency of the deletion allele, which was marginally not significant. Concerning this polymorphism, no significant differences were observed between the aggressive periodontitis and healthy control groups. In addition, no significant differences were seen amongst patients and controls when considering the +3142 C > G frequencies.Conclusion: No differences were found amongst patients and controls when considering the +3142 C > G SNP haplotypes frequencies, but a significant increased frequency of homozygotes for the 14 bp deletion allele was observed in chronic periodontitis patients compared to healthy controls, suggesting a susceptibility role of this polymorphism in the pathogenesis of this condition.

Association mapping reveals multiple QTLs for grain protein content in rice useful for biofortification.

Rice is the staple food for majority of the global population. But, rice grain has low protein content (PC). Mapping of QTLs controlling grain PC is essential for enhancement of the trait through breeding programs. A shortlisted panel population for grain protein content was studied for genetic diversity, population structure and association mapping for grain PC. Phenotyping results showed a wide variation for grain PC. The panel population showed a moderate level of genetic diversity estimated through 98 molecular markers. AMOVA and structure analysis indicated linkage disequilibrium for grain PC and deviation of Hardy-Weinberg's expectation. The analysis showed 15% of the variation among populations and 73% among individuals in the panel population. STRUCTURE analysis categorized the panel population into three subpopulations. The analysis also revealed a common primary ancestor for each subpopulation with few admix individuals. Marker-trait association using 98 molecular markers detected 7 strongly associated QTLs for grain PC by both MLM and GLM analysis. Three novel QTLs qPC3.1, qPC5.1 and qPC9.1 were detected for controlling the grain PC. Four reported QTLs viz., qPC3, QPC8, qPC6.1 and qPC12.1 were validated for use in breeding programs. Reported QTLs, qPC6, qPC6.1 and qPC6.2 may be same QTL controlling PC in rice. A very close marker RM407 near to protein controlling QTL, qProt8 and qPC8, was detected. The study provided clue for simultaneous improvement of PC with high grain yield in rice. The strongly associated markers with grain PC, namely qPC3, qPC3.1, qPC5.1, qPC6.1, qPC8, qPC9.1 and qPC12.1, will be useful for their pyramiding for developing protein rich high yielding rice.

Population genetic data of 30 insertion-deletion markers in Punjabi population of Pakistan.

Insertion-deletion polymorphism (Indels) is valuable diallelic markers for forensic as well as parentage analysis. The Investigator DIPplex Kit (Qiagen) contains thirty autosomal Indels markers along with amelogenin. These thirty markers were tested in the Pakistani Punjabi Population but no significant deviations were observed from Hardy-Weinberg equilibrium rule expectations (Bonferroni corrected) except HLD58, HLD56, HLD99, and HLD40. The mean expected and observed heterozygosity was found 0.4701 and 0.4667 respectively; combined matching probability was computed as 7.31867 × 10-13. However, the use of the 30 Indels markers proved to be a good supplementary tool in forensic casework, particularly when evidence sample is highly degraded. The significant genetic differences were also observed between the Punjabi and other populations of the world.

Cryptic species and population genetic structure of Plasmopara viticola in São Paulo State, Brazil

Downy mildew (Plasmopara viticola) is one of the most important diseases in grape‐growing areas worldwide, including Brazil. To examine pathogen population biology and structure, P. viticola was sampled during the 2015/16 growing season from 516 lesions on nine grape cultivars in 11 locations in subtropical areas of São Paulo State, Brazil. For identification of cryptic species, a subsample of 130 isolates was subjected to cleaved amplified polymorphic sequence (CAPS) analysis, and for 91 of these isolates the ITS1 region was sequenced. These analyses suggest that the population of P. viticola in São Paulo State consists of a single cryptic species, P. viticola clade aestivalis. Seven microsatellite markers were used to determine the genetic structure of all 516 P. viticola isolates, identifying 23 alleles and 55 multilocus genotypes (MLGs). Among these MLGs, 34.5% were clonal and represented 93% of the isolates sampled. Four dominant genotypes were present in at least five different locations, corresponding to 65.7% of the isolates sampled. Genotypic diversity (Ĝ = 0.21–0.89) and clonal fraction (0.58–0.96) varied among locations (populations). Most populations showed significant deviation from Hardy–Weinberg expectations; in addition, excess of heterozygosity was verified for many loci. However, principal coordinate analysis revealed no clusters among locations and no significant isolation by distance was found, suggesting high levels of migration. The results indicate that downy mildew epidemics result from multiple clonal infections caused by a few genotypes of P. viticola, and reproduction of P. viticola in São Paulo State is predominantly asexual.

Isolation and characterization of microsatellite marker loci in the Wagner’s mustached bat Pteronotus psilotis (Chiroptera: Mormoopidae) and cross-amplification in other related species

Pteronotus psilotis, a mormoopid bat, is an insectivorous, gregarious and strict cave-dwelling species that is found areas between the sea level and an elevation of about 1000 masl. This species is present in diverse habitats ranging from rain forest to dry deciduous forest. Nine microsatellite loci were developed for Wagner's mustached bat, Pteronotus psilotis using the next-generation sequencing approach, and their utility for population genetics studies was assessed. All loci were polymorphic (7-15 alleles) and characterized in 30 individuals from three P. psilotis populations, with the levels of observed and expected heterozygosity ranging from 0.280 to 0.867 and 0.584 to 0.842, respectively. One locus showed significant departures from Hardy-Weinberg expectations after Bonferroni correction. Cross-amplification in 11 other bat species was tested, for which eight microsatellites were successfully amplified, and of these seven were polymorphic. The development of these new microsatellite loci will contribute to investigations of genetic population structure, genetic diversity and gene flow in P. psilotis populations, as well as in other closely related bat species.

The Site Frequency/Dosage Spectrum of Autopolyploid Populations.

The Site Frequency Spectrum (SFS) and the heterozygosity of allelic variants are among the most important summary statistics for population genetic analysis of diploid organisms. We discuss the generalization of these statistics to populations of autopolyploid organisms in terms of the joint Site Frequency/Dosage Spectrum and its expected value for autopolyploid populations that follow the standard neutral model. Based on these results, we present estimators of nucleotide variability from High-Throughput Sequencing (HTS) data of autopolyploids and discuss potential issues related to sequencing errors and variant calling. We use these estimators to generalize Tajima's D and other SFS-based neutrality tests to HTS data from autopolyploid organisms. Finally, we discuss how these approaches fail when the number of individuals is small. In fact, in autopolyploids there are many possible deviations from the Hardy–Weinberg equilibrium, each reflected in a different shape of the individual dosage distribution. The SFS from small samples is often dominated by the shape of these deviations of the dosage distribution from its Hardy–Weinberg expectations.

New polymorphic microsatellite loci revealed for the dusky shark Carcharhinus obscurus through Ion Proton double-digest RAD sequencing.

The non-model shark species, dusky shark Carcharhinus obscurus, is a bio-economically and recreationally important shark in many areas of its range. Despite of the fishery importance of C. obscurus few genetic resources are currently available for the species. Here, we report on the isolation of eight novel microsatellite loci from C. obscurus using a double-digest restriction site associated DNA (RAD) sequencing approach on the Ion Proton semiconductor platform (ddRADseq-ion). We characterised the loci in 26 individuals and all loci were polymorphic, exhibiting 5-10 alleles (average 6.6), and observed and expected heterozygosities of 0.385-0.962 and 0.479-0.847, respectively. We found that all pairs of loci were in linkage equilibrium and conformed to Hardy-Weinberg expectations. The loci reported in this study are only the second set of microsatellite loci ever characterized for C. obscurus and will be valuable for molecular ecology studies for this vulnerable species.

Genetic diversity of Ceiba pentandra in Colombian seasonally dry tropical forest: Implications for conservation and management

Seasonally dry tropical forests (SDTFs) are one of the most degraded vegetation types worldwide and in Colombia <10% of the original cover remains. This calls for urgent conservation measures and restoration efforts. Understanding the genetic diversity and structure of tree species is crucial to inform not only conservation measures, but also sourcing of planting materials to ensure the long-term success of tree planting efforts, particularly in light of climate change. We assessed the genetic diversity distribution and structure of Ceiba pentandra from twelve representative locations of SDTF in Colombia, and how they may have been shaped by past climatic changes and human influence. We found three different genetic groups which may be the result of differentiation due to isolation of the Caribbean region, the Upper Cauca River Valley and the Patía River Valley in pre-glacial times. Range expansion of SDTF during the last glacial period, followed by more recent range contraction during the Holocene can explain the current distribution and mixture of genetic groups across contemporary STDF fragments. Most of the sampled localities showed heterozygosity scores close to Hardy–Weinberg expectations. Only two sites, among which the Patía River valley, an area with high conservation value, displayed significantly positive values of inbreeding coefficient, potentially affecting their survival and use as seed sources. While the effects of climate change might threaten C. pentandra populations across their current distribution ranges, opportunities remain for the in situ persistence of the most genetically diverse and unique ones. Based on our findings we identify priority areas for the in situ conservation of C. pentandra in Colombian SDTF and propose a pragmatic approach to guide the selection of appropriate planting material for use in restoration.

Low effective population sizes in Amblyomma variegatum, the tropical bont tick

Effective population sizes have rarely been estimated in ticks despite the importance of this parameter for evaluating the evolutionary and adaptive potential of tick populations. The present study was aimed at evaluating the effective population sizes of Amblyomma variegatum, the tropical bont tick, in three villages in Burkina Faso. For this purpose, microsatellites markers were developed. Eight out of 19 assessed markers provided good amplification results with 4 to 24 alleles recorded per marker on 216 genotyped ticks. The within-samples polymorphism was congruent with Hardy-Weinberg expectations at four markers while sex linkage and/or null alleles were observed at the others. As sampling involved two tick generations, effective population sizes were independently estimated by two methods insensitive to heterozygosity: the first one is based on linkage disequilibrium analysis within a single cohort while the second uses the changes in allele frequencies across generations. Both methods estimated the number of reproducing ticks ranging from two to a few tens reproductive adults per village and cohort. Such small estimates are congruent with the rarity of records of acaricide resistance in A. variegatum.

Karyotype characteristics and chromosomal polymorphism of Chironomus "annularius" sensu Strenzke (1959) (Diptera, Chironomidae) from the Caucasus region.

The study presents data on the karyotype characteristics and features of chromosomal polymorphism of Chironomus “annularius” sensu Strenzke (1959) (Diptera, Chironomidae) from three populations of the Caucasus region (South and Central Caucasus, and Eastern Ciscaucasia). We found 17 banding sequences in the Caucasian populations. We observed inversion polymorphism in almost all chromosome arms except for arm G. The genetic distances between all the studied populations of Ch. “annularius” were calculated using Nei criteria (1972). In spite of relative geographic proximity, the genetic distances between populations of the Caucasus are quite large, and they do not form a single cluster of Caucasian populations. The population of the South Caucasus goes to the European cluster, the population of the Central Caucasus goes to the Asian cluster and the population of Eastern Ciscaucasia does not belong to any of the outlined clusters. Principal component analysis (PCA) shows a similar picture. Two of the Caucasian populations do not follow Hardy-Weinberg expectation, there being a marked deficiency of heterozygotes in arms A, B and C, arguably, due to negative selection of heterozygotes or founder effect. All the obtained data are indicative of the complex genetic structure of Caucasian populations of Ch. “annularius” and total complexity microevolution processes occurring in the Caucasus region.

Determination of major histocompatibility class I and class II genetic composition of the Caribbean Primate Center specific pathogen-free rhesus macaque (Macaca mulatta) colony based on massively parallel sequencing.

Knowledge of major histocompatibility complex (MHC) composition and distribution in rhesus macaque colonies is critical for management strategies that maximize the utility of this model for biomedical research. Variation within the Mamu-A and Mamu-B (class I) and DRB, DQA/B, and DPA/B (class II) regions of 379 animals from the Caribbean Primate Research Center's (CPRC) specific pathogen free (SPF) colony was examined using massively parallel sequencing. Analyses of the 7 MHC loci revealed a background of Indian origin with high levels of variation despite past genetic bottlenecks. All loci exhibited mutual linkage disequilibria while conforming to Hardy-Weinberg expectations suggesting the achievement of mutation-selection balance. The CPRC's SPF colony is a significant resource for research on AIDS and other infectious agents. Characterizing colony-wide MHC variability facilitates the breeding and selection of animals bearing desired haplotypes and increases the investigator's ability to understand the immune responses mounted by these animals.