共查询到20条相似文献，搜索用时 125 毫秒
1.
Umina PA Weeks AR Kearney MR McKechnie SW Hoffmann AA 《Science (New York, N.Y.)》2005,308(5722):691-693
Geographical clines in genetic polymorphisms are widely used as evidence of climatic selection and are expected to shift with climate change. We show that the classic latitudinal cline in the alcohol dehydrogenase polymorphism of Drosophila melanogaster has shifted over 20 years in eastern coastal Australia. Southern high-latitude populations now have the genetic constitution of more northerly populations, equivalent to a shift of 4 degrees in latitude. A similar shift was detected for a genetically independent inversion polymorphism, whereas two other linked polymorphisms exhibiting weaker clinal patterns have remained relatively stable. These genetic changes are likely to reflect increasingly warmer and drier conditions and may serve as sensitive biomarkers for climate change. 相似文献
2.
Range shifts and adaptive responses to Quaternary climate change 总被引：2，自引：0，他引：2
Tree taxa shifted latitude or elevation range in response to changes in Quaternary climate. Because many modern trees display adaptive differentiation in relation to latitude or elevation, it is likely that ancient trees were also so differentiated, with environmental sensitivities of populations throughout the range evolving in conjunction with migrations. Rapid climate changes challenge this process by imposing stronger selection and by distancing populations from environments to which they are adapted. The unprecedented rates of climate changes anticipated to occur in the future, coupled with land use changes that impede gene flow, can be expected to disrupt the interplay of adaptation and migration, likely affecting productivity and threatening the persistence of many species. 相似文献
3.
Signatures of positive selection for local adaptation of African native cattle populations: A review
Wondossen AYALEW WU Xiao-yun Getinet Mekuriaw TAREKEGN CHU Min LIANG Chun-nian Tesfaye SISAY TESSEMA YAN Ping 《农业科学学报》2023,22(7):1967-1984
Cattle are central to the lives and diverse cultures of African people. It has played a crucial role in providing valuable protein for billions of households and sources of income and employment for producers and other actors in the livestock value chains. The long-term natural selection of African cattle typically signals signatures in the genome, contributes to high genetic differentiations across breeds. This has enabled them to develop unique adaptive traits to cope with inadequate feed supp... 相似文献
4.
Using a regionally calibrated model, Sinervo et al. (Reports, 14 May 2010, p. 894) predicted potential climate change impacts on lizard populations and estimated that many extinctions are under way. We argue that this model is not sufficient for predicting global losses in lizard species in response to anthropogenic climate change. 相似文献
5.
Integration of molecular genetic technology with quantitative genetic technology for maximizing the speed of genetic improvement 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Jack C.M. DEKKERS 《华南农业大学学报》2005,26(Z1)
To date,most genetic progress for quantita-tive traits in livestock has been made by selec-tion on phenotype or on estimates of breedingvalues(BBV)derived from phenotype,withoutknowledge of the number of genes that affect thetrait or the effects of each gene.In this quantita-tive genetic approach to genetic improvement,the genetic architecture of traits of interest hasessentially been treated as a‘black box’.De-spite this,the substantial rates of genetic im-provement that have been and continue to be a-chie... 相似文献
6.
Hancock AM Brachi B Faure N Horton MW Jarymowycz LB Sperone FG Toomajian C Roux F Bergelson J 《Science (New York, N.Y.)》2011,334(6052):83-86
Understanding the genetic bases and modes of adaptation to current climatic conditions is essential to accurately predict responses to future environmental change. We conducted a genome-wide scan to identify climate-adaptive genetic loci and pathways in the plant Arabidopsis thaliana. Amino acid-changing variants were significantly enriched among the loci strongly correlated with climate, suggesting that our scan effectively detects adaptive alleles. Moreover, from our results, we successfully predicted relative fitness among a set of geographically diverse A. thaliana accessions when grown together in a common environment. Our results provide a set of candidates for dissecting the molecular bases of climate adaptations, as well as insights about the prevalence of selective sweeps, which has implications for predicting the rate of adaptation. 相似文献
7.
JIANG Hui GAO Qing-rong LI Luo-jiang KONG Ling-rang ZHANG Wei-dong WU Shi-wen YANGYa-li 《中国农业科学(英文版)》2010,9(5):615-625
The male-sterile lines with Ms2 gene were highly evaluated in recurrent selection in wheat （Triticum aestivum L.）. Three populations C6 （population after six cycles of selection）, C7 （population after seven cycles of selection）, and C8 （population after eight cycles of selection） were constructed through recurrent selection with 12 parental materials （P）. Acid polyacrymide gel electrophoresis （A-PAGE） analysis was used to identify gliadin patterns and evaluate the genetic diversity in 12 parents and three populations. A total of 63 bands were identified, of which 17 polymorphic bands and 7 unique bands were present in populations and seven polymorphic bands and four unique bands were present in parents. The number of polymorphic and unique bands decreased gradually from C6 to C8, especially for to- and y-gliadins. The genetic distances in C6, C7, and C8 were calculated. The distributions of genetic distance were different in three recurrent selection populations. From C6 to C8, the genetic distance was 0.2687, 0.2652 and 0.1987, respectively. Statistically significant differences were detected between C7 and C8 with the T value of 37.9718. The result of cluster analysis based on genetic similarity matrix of three populations fitted well to those of principle coordinates analysis （PCoA）. Compared with 12 parents, almost all individuals of three populations are new genotypes. Most of the individuals from C6 and C7 could be divided into two groups, while most individuals of C8 were in one cluster. In conclusion, the results indicated that the genetic diversity was decreased severely according to the information revealed by A-PAGE, although some variations could be created in the recurrent selection. It was necessary to introduce diverse germplasm based on the genetic database of recurrent population to maintain and improve the breeding efficiency in the further program. 相似文献
8.
Comparisons of recent with historical samples of chromosome inversion frequencies provide opportunities to determine whether genetic change is tracking climate change in natural populations. We determined the magnitude and direction of shifts over time (24 years between samples on average) in chromosome inversion frequencies and in ambient temperature for populations of the fly Drosophila subobscura on three continents. In 22 of 26 populations, climates warmed over the intervals, and genotypes characteristic of low latitudes (warm climates) increased in frequency in 21 of those 22 populations. Thus, genetic change in this fly is tracking climate warming and is doing so globally. 相似文献
9.
ZHANG Hao LI Jia-qi WANG Chong LIU Xiao-hong CHEN Yao-sheng 《中国农业科学(英文版)》2005,4(11):872-876
Two pig populations were simulated with Monte Carlo method; each consisted of 5 boars and 50 sows per generation. Genetic connectedness between herds was established by randomly selecting 1 or 2 boars from one population to mate sows of the other population. Breeding pigs were selected within populations according to animal model BLUP. The benefits of genetic connectedness between herds were examined. The results showed that, the average coefficients of inbreeding decreased, while the cumulative selection responses of populations increased, and the higher response occurred randomly in the two populations at generation 5 with the increase of the genetic connectedness between herds. Selection response was affected by genetic connectedness and trait heritability, the lower heritability and higher connectedness, the better selection results. When the number of exchanged litters between populations per generation was 6 litters, the selection results reached a reflection point; if the number of exchanged litters between populations increased further from this point, neither the increase of the cumulative selection responses nor the decrease of coefficients of inbreeding was significant. 相似文献
10.
Species range expansion reduces genetic variation at the margins of a species range and should thus compromise the adaptive potential of its marginal populations. Remarkably, this prediction has not previously been tested. Here, we show that populations of the plant Mercurialis annua, which expanded its range into Spain and Portugal from North Africa after the Pleistocene glaciation, respond to selection on a key life-history trait less well than populations from the species' historical refugium. Our results provide direct evidence of a decline in adaptive potential across the geographic range of a species after a shift in its distribution. Predicting evolutionary responses to environmental change will thus need to account for the genetic heterogeneity of species and the spatial dynamics of their geographic distributions. 相似文献
11.
Two cycles of biparental mass selection （MS） and one cycle of half-sib-S3 family combining selection （HS-S3） for yield were carried out in 2 synthetic maize populations P4C0 and P5C0 synchronously. The genetic diversity of 8 maize populations, including both the basic populations and their developed populations, were evaluated by 30 SSR primers. On the 30 SSR loci, a total of 184 alleles had been detected in these populations. At each locus, the number of alleles varied from 2 to 14, with an average of 6.13. The number and ratio of polymorphic loci in both the basic populations were higher than those of their developed populations, respectively. There was nearly no difference after MS but decreased after HS-S3 in both the basic populations in the mean gene heterozygosity. The mean genetic distance changed slightly after MS but decreased in a bigger degree after HS-S3 in both the basic populations. Analyses on the distribution of genetic distances showed that the ranges of the genetic distance were wider after MS and most of the genetic distances in populations developed by HS-S3 were smaller than those in both the basic populations. The number of genotypes increased after MS but decreased after HS-S3 in both the basic populations. The genetic diversity of intra-population was much more than genetic diversity of inter-population in both the basic populations. All these indexes demonstrated that the genetic diversity of populations after MS was similar to their basic populations, and the genetic diversity was maintained during MS, whereas the genetic diversity of populations decreased after HS-S3. This result indicated that heterogeneity between some of the individuals in the developed populations increased after MS, whereas the populations become more homozygotic after HS-S3. 相似文献
12.
贵州省烟蚜遗传多样性分析 总被引：4，自引：1，他引：3
【目的】分析贵州省各生态区烟蚜（Myzus persicae）种群间是否存在遗传差异及其差异程度,探明贵州烟蚜种群异质性及种群分化情况,揭示变异发生规律及其机理,为指导虫情监测以及综合治理提供理论依据。【方法】用SSR分子标记技术对贵州省25个主要烟区的烟蚜种群进行遗传多样性分析。【结果】25个地理种群中大部分的种群呈中度分化,个别种群呈高度分化;种群遗传分化及与地理距离、海拔之间的关系分析表明,种群间的遗传距离与地理距离无显著相关性,遗传一致度与海拔差距无相关性。烟蚜种群的系统发育分析表明,25个地理种群大致分为3部分。【结论】种群的遗传分化不符合地理隔离模式,贵州省烟蚜各种群的种群分化复杂,其原因可能与贵州省特殊的地形和气候有关。 相似文献
13.
H N Kirkman 《Science (New York, N.Y.)》1971,174(4):68-70
As natural populations approach genetic equilibrium, the various genes in the population are capable of assuming intermediate distributions that might not be anticipated from either the rate of the process or the final distribution of the genes. Since it is possible that many populations have not reached genetic equilibrium, the distribution of genes in natural populations may be a reflection of the kinetic path by which the genes approach equilibrium. Attention to kinetic path provides an explanation for an apparent discrepancy in recent studies of selection in man. 相似文献
14.
杉木配合力第1轮回选择的研究 Ⅲ.速生性状的“联合选择”以及杂种优势 总被引：5，自引：2，他引：3
对杉木速生性进行联合选择结果表明:第1轮回选择中,基本群体内的表型选择(初选优树)、遗传测定林中的家系选择(逆选优树)和中选家系中的单株选择3个阶段的遗传变异都十分丰富,3阶段联合选择材积的遗传增益可达32.74%～42.13%.在杉木配合力第1轮回选择中,不同的选择方式其选择效应的大小是不同的,进行一般和特殊配合力交互轮回的效果较好,第3阶段选择的增益与选择强度有关,也与利用方式有关.优良单株出现在优良家系中的频率较大,在选择中也发现,有些家系的平均表现一般,但家系内有些个体表现优异.文中还探讨了杉木杂种优势等问题. 相似文献
15.
RAPD技术是生物DNA遗传标记中重要的研究手段，自诞生之日起就倍受青睐，广泛地应用于各生物类群的分子生物学研究。本文概述了RAPD反应的原理、及其在动物群体遗传结构测定、标记辅助选择育种等方面的应用，并探讨了RAPD技术在动物遗传育种领域的应用前景。 相似文献
16.
F J Ayala 《Science (New York, N.Y.)》1965,150(698):903-905
Changes which enhance adaptedness to the environment occur in experimental populations of Drosophila serrata which are acted upon by strong natural selection. The improvement is greater in hybrid than in single-strain populations because genetic variability is greater in the former. 相似文献
17.
对内蒙古中东部地区6个天然居群及内蒙沙芦草和蒙古冰草新品系2个栽培品种(系)的遗传多样性研究结果进行了综合评价,发现蒙古冰草具有极为丰富的遗传多样性,且居群内的遗传变异大于居群间,同时天然居群的遗传多样性也明显高于栽培品种(系);另外,两个栽培品种(系)间也存在有相当程度的遗传分化,表明了人工选择在其中所起到的重要作用;UPGMA聚类分析的结果显示,蒙古冰草的8个居群基本上可被分为与其生境土壤条件和生长条件相适应的3个类群,即沙地居群,石砾质坡地居群和沙壤质土栽培品种(系)3类,充分反映天然环境条件和人为环境条件或者说自然选择和人工选择对蒙古冰草居群间遗传分化的巨大影响. 相似文献
18.
墨白964群体5轮混合选择遗传变异的分子生物学研究 总被引：5，自引：1，他引：5
【目的】研究控制双亲的混合选择法对墨白964群体在四川生态条件下经过5轮适应性改良的效果。【方法】采用性状表型分析和SSR分子标记技术。【结果】经过5轮混合选择后，开花期性状有显著的选择增益, 多数性状的表型变异系数随着选择世代的增加有所下降。40对SSR引物在各轮群体中扩增出418个等位位点，有88.5%的遗传多样性分布于群体内，有11.5%分布于群体间。群体内的遗传多样性大于群体间的遗传多样性，且群体内的遗传差异随着选择的增加呈下降趋势。基因杂合度、多态性位点数和多态性位点百分率都呈递减趋势。原始群体C0的基因型种类多，为418种，且频率分布较散，选择后的高代群体C4、C5的基因型种类少且频率分布较集中。【结论】选择群体的遗传变异逐渐减小，这可能是由于连续对开花期性状定向选择的结果，也可能还与群体的有效含量较小和选择强度大所引起的遗传漂变有关。 相似文献
19.
油松育种系统遗传多样性研究 总被引：7，自引：1，他引：6
保持林木育种群体较高的遗传多样性是对林木进一步选择和改良的前提 ,而评价育种系统中遗传多样性变化的工作则很少 .该文以一油松育种系统中 6个群体为研究对象 ,借助水平淀粉凝胶电泳的同工酶分析方法 ,用筛选出的ACP ,ADH ,GOT ,CAT ,MDH ,PGM ,SKD ,MNR ,LAP共 9种酶系统 15个位点 ,分析了各群体间和群体内的遗传多样性状况 .研究结果表明 :①各群体内均有较高的遗传多样性水平 ;②种子园无性系群体的遗传多样性水平高于天然林 ;③种子园不同时期产生的两个自由授粉子代群体的遗传多样性与天然林子代群体相似 ;④遗传多样性参数在P0 到F2 三个世代间表现出递增趋势 ,说明改良群体可以维持较高的遗传多样性水平 ;⑤ 3个亲代群体的多数位点遵循Hardy Weinberg平衡 ,而 3个子代群体则与之相反 .该文对油松改良过程群体的遗传多样性变化及影响因素作了讨论 ,分析了群体是否遵循Hardy Weinberg平衡的原因 ,探讨了如何维持和提高种子园遗传多样性和遗传效率 ,提出了进一步研究的建议 . 相似文献
20.
海拔差异对水稻雌配子体基因型选择及其后代表型遗传分化的影响 总被引：1，自引：0，他引：1
【目的】分析海拔环境差异对水稻雌配子体基因型选择及其对后代表型遗传分化的影响,为研究植物表型对海拔环境的遗传响应及利用海拔差异进行雌配子体选择育种的方法提供理论参考。【方法】利用2个滇1型细胞质雄性不育系与耐寒粳稻地方老品种杂交,在4个具有明显海拔背景差异的试验点构建并种植了7个水稻F1雌配子体基因型选择群体及其28个F2遗传分离群体,通过估算这些世代群体的形态性状差异来检测不同海拔条件对雌配子体基因型频率变化和后代表型遗传分化的影响。【结果】对F1雌配子体基因型选择群体的形态性状分析发现,在4个不同海拔点都检测到8个性状发生了偏分离,说明海拔背景差异对F1雌配子体基因型具有选择作用,且在2 200和400 m两种海拔环境的影响都大于海拔1 860和1 250 m;产生于海拔1 860 m群体的形态性状多样性指数最大,据此随产生海拔的升高和降低,其多样性指数均减小;差异性比较显示产生于2 200 m高海拔的群体几乎与其他3个海拔产生的群体在所有性状上的差异都达显著水平。对种植于不同海拔环境的28个F2遗传分离群体的形态性状分析,结果显示海拔差异导致的雌配子体基因型选择影响其F2群体的表型遗传分化,且产生海拔差异越大,其后代表型分化就越明显。经2 200和400 m选择过的分离群体,在7个性状上检测出21处差异达显著水平;经1 860和1 250 m 选择过的分离群体,仅在3个性状上检测出6处差异达显著水平。总体变化趋势是,经高海拔2 200 m选择的群体,种植在不同海拔表现结实率高、整体生长势较差,而经低海拔400 m选择的群体的性状表现与高海拔的相反,经中海拔1 860和1 250 m选择过的群体表现多居于高、低海拔之间,但群体形态性状多样性指数较大。【结论】海拔环境差异对水稻F1雌配子体基因型具有选择作用,进而影响其后代的表型遗传分化,形成对不同海拔环境条件的生态适应性,这意味着利用海拔背景差异进行雌配子体选择育种的方法是可行的。 相似文献