Breaking the rules: modifications of sexual reproduction pathways in vertebrates.

有性生殖在大多数真核生物中普遍存在，包括减数分裂、重组、配子减少、受精、核细胞分裂和新生物体的发育。打破这一规则，脊椎动物的杂交可能会改变典型的配子发生和受精途径：出现罕见的“无性繁殖”。这样的脊椎动物可以解决关于性的持久性、配子发生和受精的基本问题。然而，从性向“无性恋”转变的原因和机制却鲜有研究。在四种二倍体和三倍体“无性”无性动物（Pelophylax）和鱼类复合体（Cobitis; Poecilia formosa）中，我们比较了不同的“无性”模式、触发因素和关键途径。利用综合方法（细胞遗传学，细胞生物学，基因组学），我们将阐明：1)通过减数分裂前基因组消除或内复制或减数分裂失败来修饰配子发生；2)受精后的精子消除；3)亲本双性恋物种和“无性”杂交种的性染色体身份，包括4)启动“无性”的潜在作用。

Sexual reproduction, prevailing in most eukaryotes, involves meiosis with recombination, reduced gametes, fertilization, karyogamy, and development of a new organism. Breaking this rule, hybridization in vertebrates may alter the canonical gametogenic and fertilization pathways: the emergence of rare "asexuality". Such vertebrates allow to address fundamental questions about the persistence of sexuality, gametogenesis and fertilization. However, causes and mechanisms of switches from sexuality to "asexuality" are poorly examined. In four diploid and triploid "asexual" anuran (Pelophylax) and fish complexes (two in Cobitis; Poecilia formosa), we compare different "asexual" modes, triggers and key pathways. Using integrative approaches (cytogenetics, cell biology, genomics), we will elucidate: 1) modifications of gametogenesis by premeiotic genome elimination or endoreplication, or failure of meiosis; 2) sperm elimination after fertilization, 3) identity of sex chromosomes in parental bisexual species and "asexual" hybrids including 4) a potential role to initiate of "asexuality".