Honeycutt Rodney L, Wilkinson Pat
Department of Organismic and Evolutionary Biology and the Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138.
Research School of Biological Sciences, The Australian National University, Canberra City, A.C.T., AUSTRALIA, 2601.
Evolution. 1989 Aug;43(5):1027-1044. doi: 10.1111/j.1558-5646.1989.tb02548.x.
Allozyme variation was examined within and between parthenogenetic clones of Warramabo virgo and the sexual ancestors, undescribed species P196 and P169. Both sexual species can be separated into northern and southern races using six loci, and the separate hybrid origin for the two major groups of parthenogenetic clones (the Standard Phylad and the Boulder-Zanthus Phylad) is substantiated by the racial variation in the sexual ancestors. Heterozygosity values in the parthenogenetic species are 6-9 times higher than those in the sexual species, and there is evidence for the accumulation of new variation subsequent to the hybrid origin of both phylads. The new variation is the result of either new mutations, recombination, or both. Three loci in the Standard Phylad clones reveal "orphan" alleles not found in the sexual ancestors; these alleles probably arose subsequent to hybridization but prior to the dispersal of the parthenogenetic clones. These data, in combination with those from other genetic studies, suggest that new variation may arise as a consequence of hybridization. Collectively, the allozyme, chromosome, molecular, and morphological data suggest that the Standard Phylad clones are of a more ancient but restricted origin, with clonal variation being the result of multiple hybridizations between individuals of P196 and P169.
对处女沼虾孤雌生殖克隆系内部以及与有性生殖祖先（未描述的物种P196和P169）之间的等位酶变异进行了研究。利用六个基因座，这两个有性生殖物种都可分为北方种群和南方种群，有性生殖祖先的种族变异证实了两个主要孤雌生殖克隆系（标准系统发育支系和博尔德-赞瑟斯系统发育支系）各自的杂交起源。孤雌生殖物种的杂合度值比有性生殖物种高6至9倍，有证据表明两个系统发育支系杂交起源后有新变异的积累。新变异是新突变、重组或两者共同作用的结果。标准系统发育支系克隆系中的三个基因座显示出在有性生殖祖先中未发现的“孤儿”等位基因；这些等位基因可能在杂交后但在孤雌生殖克隆系扩散之前出现。这些数据与其他遗传学研究的数据相结合，表明杂交可能会产生新变异。总体而言，等位酶、染色体、分子和形态学数据表明，标准系统发育支系克隆系起源更古老但范围有限，克隆变异是P196和P169个体之间多次杂交的结果。
