CORRELATED CHARACTERS IN COMPLEX GENETIC SYSTEMS

相关基因变异、选择和进化的分析方法 字符将被开发并应用于不同的系统 生物学家。 具体目标包括利用统计数据， 分子水平多态性之间的关联（连锁不平衡） 标记基因座和其他基因来解决动植物育种中的问题， 人类遗传学和进化： (i)提高人工选择的效率 作物和家畜的重要经济性状。 这将涉及最佳选择标准的推导（选择 指数），其结合了来自传统表型 测量和从分子标记位点， 与重要的数量性状相关。 约束 在长期育种计划中，标记辅助选择的效率将 通过数学和计算机模拟进行分析，包括时间 选择的最大响应极限，育种的规模 人口，获得分子和表型的相对成本 信息，遗传显性和上位性的影响， 种群的交配系统。 (ii)特定基因的精细定位，例如那些导致人类 遗传疾病、形态差异或生殖隔离 物种之间。 同时使用来自 将开发多个标记基因座以克服统计局限性 利用连锁不平衡的方法， 一次做标记。 这将有助于定位一个特定的基因， 对小于1厘摩染色体区域感兴趣， 随后通过DNA测序鉴定该基因。 (iii)遗传学在保护生物学中的应用。 协会和 分子标记基因座间的相互作用， 抑郁症（如隐性致死突变）和数量性状基因座 将分析逐渐或突然 数量减少。 了解分子遗传学 多态性与近交衰退或适应性无关 潜在的（种群灭绝的风险）将有助于减少滥用 保护生物学中的遗传学。

Methods for analyzing variation, selection and evolution of correlated characters will be developed and applied to different systems of interest to biologists. Specific aims involve the utilization of statistical associations (linkage disequilibria) between polymorphisms at molecular marker loci and other genes to solve problems in animal and plant breeding, human genetics, and evolution: (i) Augmenting the efficiency of artificial selection in the improvement of economically important characters of crop plants and domesticated animals. This will involve the derivation of optimal selection criteria (selection indices) incorporating information both from traditional phenotypic measurements and from the molecular marker loci that are statistically associated with important quantitative traits. Constraints on the efficiency of marker-assisted selection in long-term breeding programs will be analyzed mathematically and by computer simulation, including a time limit for the maximum response to selection, the size of the breeding population, the relative cost of obtaining molecular and phenotypic information, the influence of genetic dominance and epistasis, and the mating system of the population. (ii) Fine-scale mapping of particular genes, such as those causing human genetic diseases, and morphological difference or reproductive isolation between species. Methods that simultaneously employ information from multiple marker loci will be developed to overcome statistical limitations of previous methods that utilize linkage disequilibria with only one or two markers at a time. This should help to localize a particular gene of interest to a chromosomal region of less that one centimorgan, facilitating subsequent identification of the gene by DNA sequencing. (iii) Applications of genetics in conservation biology,. Associations and interactions among molecular marker loci, genes contributing to inbreeding depression (e.g. recessive lethal mutations) and quantitative trait loci will be analyzed for populations that have been gradually or suddenly reduced in numbers. Understanding situations in which molecular genetic polymorphism is not correlated with inbreeding depression or adaptive potential (risk of population extinction) will help to curtail the misuse of genetics in conservation biology.