共查询到20条相似文献,搜索用时 15 毫秒
1.
Silva MC Zuccherato LW Soares-Souza GB Vieira ZM Cabrera L Herrera P Balqui J Romero C Jahuira H Gilman RH Martins ML Tarazona-Santos E 《Genetics and molecular research : GMR》2010,9(4):2069-2085
Admixture occurs when individuals from parental populations that have been isolated for hundreds of generations form a new hybrid population. Currently, interest in measuring biogeographic ancestry has spread from anthropology to forensic sciences, direct-to-consumers personal genomics, and civil rights issues of minorities, and it is critical for genetic epidemiology studies of admixed populations. Markers with highly differentiated frequencies among human populations are informative of ancestry and are called ancestry informative markers (AIMs). For tri-hybrid Latin American populations, ancestry information is required for Africans, Europeans and Native Americans. We developed two multiplex panels of AIMs (for 14 SNPs) to be genotyped by two mini-sequencing reactions, suitable for investigators of medium-small laboratories to estimate admixture of Latin American populations. We tested the performance of these AIMs by comparing results obtained with our 14 AIMs with those obtained using 108 AIMs genotyped in the same individuals, for which DNA samples is available for other investigators. We emphasize that this type of comparison should be made when new admixture/population structure panels are developed. At the population level, our 14 AIMs were useful to estimate European admixture, though they overestimated African admixture and underestimated Native American admixture. Combined with more AIMs, our panel could be used to infer individual admixture. We used our panel to infer the pattern of admixture in two urban populations (Montes Claros and Manhua?u) of the State of Minas Gerais (southeastern Brazil), obtaining a snapshot of their genetic structure in the context of their demographic history. 相似文献
2.
A. M. Serebryanyi M. M. Antoshchina A. V. Aleschenko N. I. Ryabchenko I. I. Pelevina 《Cell and Tissue Biology》2008,2(3):333-336
Blood lymphocytes of 15 healthy donors have been investigated for their ability to reduce radiosensitivity after low-dose irradiation-radio-induced adaptive response (AR). The frequency of unstable chromosome aberrations was used to evaluate cell radiosensitivity after the irradiation of cells in low adaptive (5 cGy) and high challenge (1 Gy) doses in comparison with the effect of challenge irradiation only. Three indexes have been used, i.e., (A) the frequency of cells with aberrations per total analyzed cell, (B) the number of chromosome aberrations per one cell, (C) and the number of chromosome aberrations per one aberrant cell. It was found that the donors can be divided in the four following groups: 1. AR was not estimated any of the indexes used; 2. AR was estimated with indexes A and B, but not C; 3. AR was shown by indexes B and C; 4. AR was evident with all three indexes. The generally accepted AR repair model only explains the appearance of group-3 and-4 donors, but not group-2. For the purpose of understanding the AR mechanisms and the difference in AR estimations with various criteria, the metaphase distribution by the number of chromosome aberrations has been analyzed for each donor. It was shown that, in group-2 donors, the number of cells without aberrations after adaptive and challenge irradiations was significantly higher than after irradiation with a challenge dose only. Thus, in this group, AR is formed as a result of the changed frequency of cells in the 0 class (population shift). A similar shift is observed in the metaphase distribution in the donors of group 4, but not in group 3. The data obtained show that AR is probably a result of several processes, including the activation of the reparation of premutational genome damages, population shifts evident in the frequency of undamaged cells, and, possibly, the activation of apoptotic cell death. The complex character of AR is reflected to different degrees in each criterion of radiosensitivity. 相似文献
3.
Masahiro Nakaoka 《Population Ecology》1996,38(2):141-152
Recent developments of the theory of stochastic matrix modeling have made it possible to estimate general properties of age- and size-structured populations in fluctuating environments. However, applications of the theory to natural populations are still few. The empirical studies which have used stochastic matrix models are reviewed here to examine whether predictions made by the theory can be generally found in wild populations. The organisms studied include terrestrial grasses and herbs, a seaweed, a fish, a reptile, a deer and some marine invertebrates. In all the studies, the stochastic population growth rate (ln λ s ) was no greater than the deterministic population growth rate determined using average vital rates, suggesting that the model based only on average vital rates may overestimate growth rates of populations in fluctuating environments. Factors affecting ln λ s include the magnitude of variation in vital rates, probability distribution of random environments, fluctuation in different types of vital rates, covariances between vital rates, and autocorrelation between successive environments. However, comprehensive rules were hardly found through the comparisons of the empirical studies. Based on shortcomings of previous studies, I address some important subjects which should be examined in future studies. 相似文献
4.
K V Richter 《Folia haematologica (Leipzig, Germany : 1928)》1989,116(3-4):445-450
Possible donors may be recommended by the following order: 1. HLA-identical twins (syngeneic) 2. HLA-identical siblings 3. HLA-haploidentical related donors The increased number of additional HLA-incompatibilities (HLA-A, -B, -DR) increases the risk of GVHD. 4. HLA-phenoidentical and MLC-negative unrelated donors The DRS for BMT includes the early HLA typing of the patient and of all related potential donors, covering all known antigens. Evidence on the basis of MLC should be available for cellular non-reactivity between donor and recipient cells, although this will be rarely possible with haploidentical related donors. Donor-specific HLA antibodies must not be detectable in the recipient. No generally accepted method has so far become available for consideration of minor histocompatibility antigens in the context of DRS for BMT. 相似文献
5.
Qiong Zhang Zhi-Gao Zeng Ya-Jie Ji De-Xing Zhang Yan-Ling Song 《Conservation Genetics》2008,9(3):507-514
Hainan Eld’s deer (Cervus eldi hainanus) experienced a dramatic decline in the late 1960s through early 1970s and by 1976 only 26 deer remained in Datian of Hainan
Island, China. Since then, conservation efforts have successfully rescued this deer from extinction. We employed 10 microsatellite
DNA loci to index genetic variation in the one source (Datian) and two introduced populations (Bangxi and Ganshiling) and
suggest implications for the conservation of the species. A total of 40 alleles at 10 loci were examined from 198 deer blood
samples. The source population harbored all 40 alleles, while the Bangxi and Ganshiling translocated populations contained
24 and 26 alleles, respectively. The genetic variability was low (H
e
≈ 0.33) for each of the three populations. No significant difference in genetic variability between the three populations
was detected (P > 0.05); yet significant differentiation was found among the three populations. Our results suggest that founder effects
and genetic drift have affected the two translocated populations. For conservation we recommend the three populations be managed
as a meta-population. When establishing future reintroductions, the founder population should have a size larger than the
original 26 founders in Datian population or be composed of a cohort of over 20 same-age individuals with 1:1 sex ratio. Genetic
monitoring for both the source and translocated populations should be continuously conducted in order to assess the effectiveness
of deer conservation in the future. 相似文献
6.
What regulate and limit reindeer populations in Norway? 总被引:5,自引:0,他引:5
Torkild Tveraa Per Fauchald Nigel Gilles Yoccoz Rolf Anker Ims Ronny Aanes Kjell Arild Høgda 《Oikos》2007,116(4):706-715
An understanding of how species are affected by top-down and bottom-up processes in food webs, and how these forces interact with climatic conditions is crucial for how ecosystems should be managed. In Norway large carnivores are effectively removed from extensive areas to protect livestock, leaving human harvesting as the only significant top-down force on ungulate populations. We examined the relative role of top-down and bottom-up processes for 58 semi-domesticated reindeer populations in Norway subjected to contrasting climatic regimes over the period 1981–2005. Intensive herding and international agreement have resulted in a situation where some populations are unable to undertake seasonal migration to the interior to escape the unfavourable climatic conditions that rule the coastal region in the winter, a critical season for northern ungulates. We used this natural manipulation to contrast between populations with 'poor' and 'good' winter conditions. For populations with good winter conditions, average body size increased with harvesting, suggesting that some top-down process was necessary to avoid food limitation. Time-series analyses revealed that direct regulation of population size was only evident in populations subjected to intensive harvesting. The lack of direct regulation in populations subjected to low harvesting resulted in high vulnerability to harsh winter weather. The body size and climate vulnerability of populations with poor winter conditions was unaffected of harvesting, but average densities was positively related to overall vegetation productivity as indexed by satellite images (NDVI). Top-down processes appeared to be necessary to dampen the effect of harsh winters in populations with generally good winter conditions. Conversely, populations subjected to generally poor winter conditions appeared to be more influenced by bottom-up processes and buffered climatic perturbations by increasing body size. 相似文献
7.
R. J. Bellamy C. F. Inglehearn I. K. Jalili A. J. Jeffreys S. S. Bhattacharya 《Human genetics》1991,87(3):341-347
Summary We have compared band sharing between the DNA fingerprints of members of an inbred human population with band sharing between members of an outbred population. It had not previously been determined whether the high rate of mutation at minisatellite loci is sufficient to prevent an increase in band sharing in moderately inbred populations. We have found that there is an increase in band sharing in the 2-kb to 9-kb size range, but not in the >9-kb size range, in the inbred population. The difference was consistently observed using four different multi-locus probes, viz. 33.6, 33.15, (CAC)5 and M13. Thus, we have demonstrated that moderate but prolonged inbreeding can lead to increased similarity in human DNA fingerprints. This should be considered when analysing DNA fingerprints in forensic or paternity cases involving members of an inbred community. 相似文献
8.
Alexandre Millon Xavier Lambin Sbastien Devillard Michael Schaub 《Biological reviews of the Cambridge Philosophical Society》2019,94(6):2049-2067
The demography of a population is often reduced to the apparent (or local) survival of individuals and their realised fecundity within a study area defined according to logistical constraints rather than landscape features. Such demographics are then used to infer whether a local population contributes positively to population dynamics across a wider landscape context. Such a simplistic approach ignores a fundamental process underpinning population dynamics: dispersal. Indeed, it has long been accepted that immigration contributed by dispersers that emigrated from neighbouring populations may strongly influence the net growth of a local population. To date however, we lack a clear picture of how widely immigration rate varies both among and within populations, in relation to extrinsic and intrinsic ecological conditions, even for the best‐studied avian and mammalian populations. This empirical knowledge gap precludes the emergence of a sound conceptual framework that ought to inform conservation and population ecology. This review, conducted on both birds and mammals, has thus three complementary objectives. First, we describe and evaluate the relative merits of methods used to quantify immigration and how they relate to widely applicable metrics. We identify two simple and unifying metrics to measure immigration: the immigration rate it defined as the ratio of the number of immigrants present in the population at time t + 1 and the total breeding population in year t, and πt , the proportion of immigrants among new recruits (i.e. new breeders). Two recently developed methods are likely to provide the most valuable data on immigration in the near future: individual parentage (rather than population) assignments based on genetic sampling, and spatially explicit integrated population models combining multiple sources of demographic data (survival, fecundity and population counts). Second, we report on a systematic literature review of studies providing a quantitative measure of immigration. Although the diversity of methods employed precludes detailed analyses, it appears that the number of immigrants exceeds locally born individuals in recruitment for most avian populations (median πt = 0.57, N = 45 estimates from 37 studies), a figure twofold higher than estimated for mammalian populations (median πt = 0.26, N = 33 estimates from 11 studies). Third, recent quantitative studies reveal that immigration can be the main driver of temporal variation in population growth rates, across a wide array of demographic and spatial contexts. To what extent immigration acts as a regulatory process has however been considered only rarely to date and deserves more attention. Overall, it is likely that most populations benefit from immigrants without necessarily being sink populations. Furthermore, we suggest that quantitative estimates of immigration should be core to future demographic studies and plead for more empirical evidence about the ways in which immigration interacts with local demographic processes to shape population dynamics. Finally, we discuss how to tackle spatial population dynamics by exploring, beyond the classical source–sink framework, the extent to which populations exchange individuals according to spatial scale and type of population distribution throughout the landscape. 相似文献
9.
Christian Barnabe Rosio Buitrago Philippe Bremond Claudia Aliaga Renata Salas Pablo Vidaurre Claudia Herrera Frédérique Cerqueira Marie-France Bosseno Etienne Waleckx Simone Frédérique Breniere 《PloS one》2013,8(11)
Trypanosoma cruzi, the causative agent of Chagas disease, is subdivided into six discrete typing units (DTUs; TcI–TcVI) of which TcI is ubiquitous and genetically highly variable. While clonality is the dominant mode of propagation, recombinant events play a significant evolutive role. Recently, foci of wild Triatoma infestans have been described in Bolivia, mainly infected by TcI. Hence, for the first time, we evaluated the level of genetic exchange within TcI natural potentially panmictic populations (single DTU, host, area and sampling time). Seventy-nine TcI stocks from wild T. infestans, belonging to six populations were characterized at eight microsatellite loci. For each population, Hardy-Weinberg equilibrium (HWE), linkage disequilibrium (LD), and presence of repeated multilocus genotypes (MLG) were analyzed by using a total of seven statistics, to test the null hypothesis of panmixia (H0). For three populations, none of the seven statistics allowed to rejecting H0; for another one the low size did not allow us to conclude, and for the two others the tests have given contradictory results. Interestingly, apparent panmixia was only observed in very restricted areas, and was not observed when grouping populations distant of only two kilometers or more. Nevertheless it is worth stressing that for the statistic tests of "HWE", in order to minimize the type I error (i. e. incorrect rejection of a true H0), we used the Bonferroni correction (BC) known to considerably increase the type II error ( i. e. failure to reject a false H0). For the other tests (LD and MLG), we did not use BC and the risk of type II error in these cases was acceptable. Thus, these results should be considered as a good indicator of the existence of panmixia in wild environment but this must be confirmed on larger samples to reduce the risk of type II error. 相似文献
10.
Understanding how genetic variation is maintained within a species is important in ecology, evolution, conservation and population genetics. Tremendous efforts have been made to evaluate the patterns of genetic variation in natural populations of various species. For this purpose, microsatellites have played a major role since the 1990s. Here we describe a comprehensive database, varver (Variation in Vertebrates) that provides complete information regarding microsatellite variation in natural populations of vertebrates. For each species, varver includes basic information of the species, a list of publications reporting the microsatellite variation, and tables of genetic variation within and between populations (heterozygosity and FST). The geographic location and rough sampling range are also shown for each sampled population. The database should be useful for researchers interested in not only specific species but also comparing multiple species. We discuss the utility of microsatellite data, particularly for meta‐analyses that involve multiple microsatellite loci from various species. We show that in such analyses, it is extremely important to correct for biases caused by differences in mutation rate, mainly due to repeat unit and number. 相似文献
11.
Katie N. Bertrand Justin A. VanDeHey Tyler J. Pilger Eli A. Felts Thomas F. Turner 《Conservation Genetics》2016,17(4):775-784
A peripheral population of mountain sucker, Pantosteus jordani, located in the Black Hills of South Dakota, USA, represents the eastern-most range of the species and is completely isolated from other populations. Over the last 50 years, mountain sucker populations have declined in the Black Hills, and now only occur in 40 % of the historic local range, with densities decreasing by more than 84 %.We used microsatellite DNA markers to estimate genetic diversity and to assess population structure across five streams where mountain suckers persist. We evaluated results in the context of recent ecological surveys to inform decisions about mountain sucker conservation. Significant allele frequency differences existed among sample streams (Global FST = 0.041) but there was no evidence of isolation by distance. Regionally, genetic effective size, Ne, was estimated to be at least 338 breeding individuals, but Ne within streams was expected to be less. Despite almost complete demographic isolation and reduced population size, there appears to be little evidence of inbreeding, but genetic drift and local isolation due to fragmentation probably best explains genetic structure in this peripheral mountain sucker population. Recommended strategies for population enhancement include restoration of stream connectivity and habitat improvement. Moreover, repatriation and assisted movement (i.e., gene flow) of fishes should maximize genetic diversity in stream fragments in the Black Hills region. 相似文献
12.
Sandra Regina Rachadel Torres Clineu Julien Seki Uehara Ana Frederica Sutter-Latorre Bibiana Sgorla de Almeida Tania Streck Sauerbier Yara Costa Netto Muniz Andrea Rita Marrero Ilíada Rainha de Souza 《Molecular biology reports》2014,41(8):5429-5433
The application of DNA technology in forensic investigations has grown rapidly in the last 25 years and with an exponential increase of short tandem repeats (STRs) data, usually presented as allele frequencies, that may be later used as databases for forensic and population genetics purposes. Thereby, classes of molecular markers such as single nucleotide polymorphisms and insertions/deletions (InDels) have been presented as another option of genetic marker sets. These markers can be used in paternity cases, when mutations in STR polymorphisms are present, as well as in highly degraded DNA analysis. In the present study, the allele frequencies and heterozygosity (H) of a 30 InDel markers set were determined and the forensic efficacy was evaluated through estimation of discrimination power (DP), match probability, typical paternity index and power of paternity exclusion in 108 unrelated volunteers from the State of Santa Catarina (South Brazil). The observed H per locus showed a range between 0.370 and 0.574 (mean = 0.479). HLD128 was the locus with the highest DP (DP = 0.656). DP for all markers combined was greater than 99.9999999999646 % which provides satisfactory levels of information for forensic demands. Genetic comparisons (exact tests of population differentiation and pairwise genetic distances) revealed that the population of Santa Catarina State differs from Korea and USA Afro-American populations but is similar to the Portuguese, German, Polish, Spanish and Basque populations. 相似文献
13.
Demographic responses to weather fluctuations are context dependent in a long‐lived amphibian
下载免费PDF全文
![点击此处可从《Global Change Biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hugo Cayuela Dragan Arsovski Jean‐Marc Thirion Eric Bonnaire Julian Pichenot Sylvain Boitaud Claude Miaud Pierre Joly Aurélien Besnard 《Global Change Biology》2016,22(8):2676-2687
Weather fluctuations have been demonstrated to affect demographic traits in many species. In long‐lived organisms, their impact on adult survival might be buffered by the evolution of traits that reduce variation in interannual adult survival. For example, skipping breeding is an effective behavioral mechanism that may limit yearly variation in adult survival when harsh weather conditions occur; however, this in turn would likely lead to strong variation in recruitment. Yet, only a few studies to date have examined the impact of weather variation on survival, recruitment and breeding probability simultaneously in different populations of the same species. To fill this gap, we studied the impact of spring temperatures and spring rainfall on survival, on reproductive skipping behavior and on recruitment in five populations of a long‐lived amphibian, the yellow‐bellied toad (Bombina variegata). Based on capture–recapture data, our findings demonstrate that survival depends on interactions between age, population and weather variation. Varying weather conditions in the spring result in strong variation in the survival of immature toads, whereas they have little effect on adult toads. Breeding probability depends on both the individual's previous reproductive status and on the weather conditions during the current breeding season, leading to high interannual variation in recruitment. Crucially, we found that the impact of weather variation on demographic traits is largely context dependent and may thus differ sharply between populations. Our results suggest that studies predicting the impact of climate change on population dynamics should be taken with caution when the relationship between climate and demographic traits is established using only one population or few populations. We therefore highly recommend further research that includes surveys replicated in a substantial number of populations to account for context‐dependent variation in demographic processes. 相似文献
14.
《PloS one》2014,9(5)
The understanding of the complex genotype-phenotype architecture of human pigmentation has clear implications for the evolutionary history of humans, as well as for medical and forensic practices. Although dozens of genes have previously been associated with human skin color, knowledge about this trait remains incomplete. In particular, studies focusing on populations outside the European-North American axis are rare, and, until now, admixed populations have seldom been considered. The present study was designed to help fill this gap. Our objective was to evaluate possible associations of 18 single nucleotide polymorphisms (SNPs), located within nine genes, and one pseudogene with the Melanin Index (MI) in two admixed Brazilian populations (Gaucho, N = 352; Baiano, N = 148) with different histories of geographic and ethnic colonization. Of the total sample, four markers were found to be significantly associated with skin color, but only two (SLC24A5 rs1426654, and SLC45A2 rs16891982) were consistently associated with MI in both samples (Gaucho and Baiano). Therefore, only these 2 SNPs should be preliminarily considered to have forensic significance because they consistently showed the association independently of the admixture level of the populations studied. We do not discard that the other two markers (HERC2 rs1129038 and TYR rs1126809) might be also relevant to admixed samples, but additional studies are necessary to confirm the real importance of these markers for skin pigmentation. Finally, our study shows associations of some SNPs with MI in a modern Brazilian admixed sample, with possible applications in forensic genetics. Some classical genetic markers in Euro-North American populations are not associated with MI in our sample. Our results point out the relevance of considering population differences in selecting an appropriate set of SNPs as phenotype predictors in forensic practice. 相似文献
15.
Hitoshi Kubota Katsutoshi Watanabe Naoyuki Suguro Masaaki Tabe Kazuhiro Umezawa Seiichi Watanabe 《Conservation Genetics》2010,11(6):2343-2355
The Tokyo bitterling Tanakia tanago (Cyprinidae) was once found throughout the Kanto Plain, central Japan, but most of their habitats have been lost due to human
activities such as urbanization and improvement of paddy fields. Subsequently, conservation efforts, including captive breeding
and reintroduction, have been ongoing. However, the genetic relationships among populations of this species including captive
and remnant wild populations have been uncertain and thus management units for this species have been unidentified. We examined
the population differentiation among 12 populations, including four wild and eight captive populations, and their relative
genetic diversities to assist in conservation management decisions. Phylogeographic analyses based on partial mitochondrial
cytochrome b gene sequences and microsatellite polymorphisms revealed four geographically associated genetic groups in the populations.
Northern Tochigi populations have diverged from other populations (0.77% of d
A
), likely stemming from allopatric fragmentation following a change in the route of the Naka River, which occurred during
the middle of the Pleistocene epoch. Microsatellite analysis has revealed that the genetic diversity of each population is
generally low, and that most of the populations have experienced genetic bottlenecks. For future in- and ex-situ conservation
programs to succeed, the population structure and genetic variability of remnant populations need to be taken into consideration. 相似文献
16.
María Inés Fariello Simon Boitard Hugo Naya Magali SanCristobal Bertrand Servin 《Genetics》2013,193(3):929-941
The detection of molecular signatures of selection is one of the major concerns of modern population genetics. A widely used strategy in this context is to compare samples from several populations and to look for genomic regions with outstanding genetic differentiation between these populations. Genetic differentiation is generally based on allele frequency differences between populations, which are measured by FST or related statistics. Here we introduce a new statistic, denoted hapFLK, which focuses instead on the differences of haplotype frequencies between populations. In contrast to most existing statistics, hapFLK accounts for the hierarchical structure of the sampled populations. Using computer simulations, we show that each of these two features—the use of haplotype information and of the hierarchical structure of populations—significantly improves the detection power of selected loci and that combining them in the hapFLK statistic provides even greater power. We also show that hapFLK is robust with respect to bottlenecks and migration and improves over existing approaches in many situations. Finally, we apply hapFLK to a set of six sheep breeds from Northern Europe and identify seven regions under selection, which include already reported regions but also several new ones. We propose a method to help identifying the population(s) under selection in a detected region, which reveals that in many of these regions selection most likely occurred in more than one population. Furthermore, several of the detected regions correspond to incomplete sweeps, where the favorable haplotype is only at intermediate frequency in the population(s) under selection. 相似文献
17.
T. Sjøvold 《Human Evolution》1990,5(5):431-447
Estimation of stature from skeletal measurements is of great interest in some studies, e.g. in forensic anthropology, where
victims have to be identified. A problem occurring in practice is that the individual whose stature has to be assessed is
in general from an unknown population. Alternatives to ordinary least squares regression are discussed. Application of available
information about stature/long bone proportions leads to a general proposal called thethe weighted line of organic correlation, which is fitted to a wide range of populations. The effects of sex and race upon this line are practically negligible. These
properties makes it suitable for use not only for forensic purposes, but also for the estimation of stature based on skeletons
or skeletal populations from the past. 相似文献
18.
Eric Routman 《Journal of evolutionary biology》1993,6(3):329-357
Genetic relationships, population subdivision and genetic diversity were estimated from mtDNA and allozyme data for two subspecies of tiger salamander, one of which is obligately metamorphic and the other polymorphic for paedomorphosis (larval reproduction). Far greater genetic differentiation exists between subspecies than within subspecies, suggesting that the subspecies have evolved in allopatry. Values of Fst calculated from both mtDNA and allozymes were greater than 0.400 for each subspecies. Significant population subdivision was detected even on a microgeographic scale. This extensive population subdivision indicates that populations can respond to extremely localized selection pressures. In the case of paedomorphosis, populations in permanent water should evolve paedomorphosis as long as the appropriate genes exist. For both mtDNA and allozymes, comparisons of population structure within the polymorphic subspecies and between polymorphic and metamorphic subspecies reveal no discernible effects of paedomorphosis. However, a comparison of paedomorphic and metamorphic populations of the polymorphic subspecies showed significantly higher mtDNA diversity in paedomorphic populations. The discrepancy between the allozyme and mtDNA results may be due to the lower effective population size of mtDNA compared to autosomal genes. 相似文献
19.
Individual inversions or their combinations: which is the main selective target in a natural population of Drosophila subobscura?
下载免费PDF全文
![点击此处可从《Journal of evolutionary biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
It is generally accepted that chromosomal inversions have been key elements in adaptation and speciation processes. In this context, Drosophila subobscura has been, and still is, an excellent model species due to its rich chromosomal polymorphism. In this species, many analyses from natural populations have demonstrated the adaptive potential of individual inversions (and their overlapped combinations, the so‐called arrangements). However, little information is available on the evolutionary role of combinations generated by inversions located in homologous and nonhomologous chromosomes. The aim of this research was to ascertain whether these combinations are also a target for natural selection. For this objective, we have studied the inversion composition of homologous and nonhomologous chromosomes from a D. subobscura sample collected in a well‐studied population, Mount Avala (Serbia). No significant deviation from H‐W expectations was detected, and when comparing particular karyotypic combinations, likelihood ratios close to 1 were obtained. Thus, it seems that for each pair of homologous chromosomes inversions no deviation from randomness was detected. Finally, no linkage disequilibrium was observed between inversions located in different chromosomes of the karyotype. For all these reasons, it can be assumed that, at the cytological level, the individual inversions rather than their combinations in different chromosomes are the main target of selection. 相似文献
20.