Gopurenko David, Williams Rod N, McCormick Cory R, DeWoody J Andrew
Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA.
Mol Ecol. 2006 Jun;15(7):1917-28. doi: 10.1111/j.1365-294X.2006.02904.x.
Among urodeles, ambystomatid salamanders are particularly amenable to genetic parentage analyses because they are explosive aggregate breeders that typically have large progeny arrays. Such analyses can lead to direct inferences about otherwise cryptic aspects of salamander natural history, including the rate of multiple mating, individual reproductive success, and the spatial distribution of clutches. In 2002, we collected eastern tiger salamander (Ambystoma tigrinum tigrinum) egg masses (> 1000 embryos) from a approximately 80 m linear transect in Indiana, USA. Embryos were genotyped at four variable microsatellite loci and the resulting progeny array data were used to reconstruct multilocus genotypes of the parental dams and sires for each egg mass. UPGMA analysis of genetic distances among embryos resolved four instances of egg mass admixture, where two or more females had oviposited at exactly the same site resulting in the mixing of independent cohorts. In total, 41 discrete egg masses were available for parentage analyses. Twenty-three egg masses (56%) consisted exclusively of full-siblings (i.e. were singly sired) and 18 (44%) were multiply sired (mean 2.6 males/clutch). Parentage could be genetically assigned to one of 17 distinct parent pairs involving at least 15 females and 14 different males. Reproductive skew was evident among males who sired multiply sired clutches. Additional evidence of the effects of sexual selection on male reproductive success was apparent via significant positive correlations between male mating and reproductive success. Females frequently partitioned their clutches into multiple discrete egg masses that were separated from one another by as many as 43 m. Collectively, these data provide the first direct evidence for polygynandry in a wild population of tiger salamanders.
在有尾目动物中，钝口螈科蝾螈特别适合进行遗传亲权分析，因为它们是爆发式聚集繁殖者，通常会产生大量的后代。这样的分析可以直接推断蝾螈自然史中其他隐秘的方面，包括多次交配的频率、个体的繁殖成功率以及卵块的空间分布。2002年，我们在美国印第安纳州一条约80米长的线性样带上收集了东部虎螈（Ambystoma tigrinum tigrinum）的卵块（超过1000个胚胎）。对胚胎在四个可变微卫星位点进行基因分型，并利用所得的后代阵列数据重建每个卵块中亲本雌螈和雄螈的多位点基因型。对胚胎之间遗传距离的UPGMA分析解析出了4例卵块混合的情况，即两个或更多雌性在完全相同的地点产卵，导致独立的群体混合。总共有41个离散的卵块可用于亲权分析。23个卵块（56%）完全由全同胞组成（即由单一雄性授精），18个（44%）是由多个雄性授精（平均每个卵块有2.6个雄性）。亲权可以通过基因鉴定到17个不同的亲本对中的一个，涉及至少15只雌性和14只不同的雄性。在使卵块有多个雄性授精的雄性中，生殖偏斜很明显。通过雄性交配与生殖成功之间的显著正相关，性选择对雄性生殖成功影响的其他证据也很明显。雌性经常将它们的卵块分成多个离散的卵块，这些卵块彼此之间相隔多达43米。总体而言，这些数据为野生虎螈种群中的多雌多雄制提供了首个直接证据。
