由于有害的等位基因比较容易在雄性二倍体个体中纯合，人们通常认为致命遗传因子只对二倍体生物产生作用，而对单倍二倍体生物没有影响。然而最近加拿大的2位科学家发现．对于膜翅目的单倍二倍体生物（比如蚂蚁、蜜蜂和黄蜂等），单基...由于有害的等位基因比较容易在雄性二倍体个体中纯合，人们通常认为致命遗传因子只对二倍体生物产生作用，而对单倍二倍体生物没有影响。然而最近加拿大的2位科学家发现．对于膜翅目的单倍二倍体生物（比如蚂蚁、蜜蜂和黄蜂等），单基因座位的补充性别决定通过在性基因座位上的纯合产生相当的遗传负荷，而导致死亡或不育的二倍休雄性。通过构建随机模型，可以发现二倍体雄性的产生（diploid male production，DMP）可以引起一个快速的、不典型的灭绝旋涡（见右图）。展开更多
Marine invertebrates and fish are well known for their remarkable genetic diversity, which is commonly explained by large population size and the characteristic dispersive nature of their early, planktonic life histor...Marine invertebrates and fish are well known for their remarkable genetic diversity, which is commonly explained by large population size and the characteristic dispersive nature of their early, planktonic life history. Other potential sources of diversity in marine animals, such as a higher mutation rate, have been much less considered, though evidence for a high genetic load in marine bivalves has been accumulating for nearly half a century. In this review, I examine evidence for a higher genetic load in marine animals from studies of molecular marker segregation and linkage over the last 40 years, and survey recent work examining mutational load with molecular evolution approaches. Overall, marine animals appear to have higher genetic load than terrestrial animals （higher dn/ds ratios, inbreeding load, and segregation dis＇tortion）, though results are mixed for marine fish and data are lacking for many marine animal groups. Bivalves （oysters） have the highest loads observed among marine animals, comparable only to long-lived plants; however, more data is needed from other bivalves and more marine invertebrate taxa generally. For oysters, a higher load may be related to a chronically lower effective population size that, in concert with a higher mutational rate, elevate the number of deleterious mutations observed. I suggest that future studies use high-throughput sequencing approaches to examine （1） polymorphism in genomescale datasets across a wider range of marine animals at the population level and （2） intergenerational mutational changes between parents and offspring in crosses of aquaculture species to quantify mutation rates.展开更多
文摘由于有害的等位基因比较容易在雄性二倍体个体中纯合，人们通常认为致命遗传因子只对二倍体生物产生作用，而对单倍二倍体生物没有影响。然而最近加拿大的2位科学家发现．对于膜翅目的单倍二倍体生物（比如蚂蚁、蜜蜂和黄蜂等），单基因座位的补充性别决定通过在性基因座位上的纯合产生相当的遗传负荷，而导致死亡或不育的二倍休雄性。通过构建随机模型，可以发现二倍体雄性的产生（diploid male production，DMP）可以引起一个快速的、不典型的灭绝旋涡（见右图）。
文摘Marine invertebrates and fish are well known for their remarkable genetic diversity, which is commonly explained by large population size and the characteristic dispersive nature of their early, planktonic life history. Other potential sources of diversity in marine animals, such as a higher mutation rate, have been much less considered, though evidence for a high genetic load in marine bivalves has been accumulating for nearly half a century. In this review, I examine evidence for a higher genetic load in marine animals from studies of molecular marker segregation and linkage over the last 40 years, and survey recent work examining mutational load with molecular evolution approaches. Overall, marine animals appear to have higher genetic load than terrestrial animals （higher dn/ds ratios, inbreeding load, and segregation dis＇tortion）, though results are mixed for marine fish and data are lacking for many marine animal groups. Bivalves （oysters） have the highest loads observed among marine animals, comparable only to long-lived plants; however, more data is needed from other bivalves and more marine invertebrate taxa generally. For oysters, a higher load may be related to a chronically lower effective population size that, in concert with a higher mutational rate, elevate the number of deleterious mutations observed. I suggest that future studies use high-throughput sequencing approaches to examine （1） polymorphism in genomescale datasets across a wider range of marine animals at the population level and （2） intergenerational mutational changes between parents and offspring in crosses of aquaculture species to quantify mutation rates.
