Collaborative Research: mtDNA and the Evolution of Fishes

Vrijenhoek和Avise将调查单性Poeciliopsis鱼类及其双性祖先的线粒体DNA （mtDNA）变异和系统发育，以利用这些非典型遗传系统提供的独特优势，解决对进化生物学具有广泛意义的两个问题：(1)mtDNA的遗传是否严格地来自母系？(2)无性繁殖和半有性繁殖的脊椎动物的进化寿命和系统发育关系是什么？将对杂交遗传菌株进行研究，以寻找来自父本的mtDNA的证据，表明偶尔有低水平的“父本泄漏”mtDNA进入受精卵。本文将从mtDNA系统发育的角度对雌性和杂交性青豆进行研究。通过比较单性菌株及其有性繁殖的祖先体内和之间的mtDNA变异，研究人员将估计该复合体中鱼类的年龄、克隆多样性和系统发育起源。结果应该有助于解决长期以来对单性类群进化寿命的关注，从而解决无性生殖的进化后果。

Vrijenhoek and Avise will survey mitochondrial DNA (mtDNA) variation and phylogeny in unisexual Poeciliopsis fishes and their bisexual progenitors in order to capitalize upon the unique advantages afforded by these atypical genetic systems for addressing two questions of broad significance to evolutionary biology: (1) is the inheritance of mtDNA strictly maternal? and (2) what are the evolutionary longevities and phylogenetic relationships of vertebrates that reproduce by asexual or semi- sexual means? The hybridogenetic strains will be studied for evidence of paternally-derived mtDNA indicative of occasional, low-level "paternal leakage" of mtDNA into zygotes. Both gynogenetic and hybridogenetic Poeciliopsis will be studied in terms of mtDNA phylogeny. By comparing mtDNA variability within and among the unisexual strains and their sexually-reproducing progenitors, the investigators will estimate the ages, clonal diversities, and phylogenetic origins of fish in this complex. Results should help in addressing long-standing concerns about the evolutionary longevities of unisexual taxa, and hence about the evolutionary consequences of asexual reproduction.