ECOLOGY AND EVOLUTION OF SYMPATRIC STICKLEBACKS (GASTEROSTEUS) - EVIDENCE FOR A SPECIES-PAIR IN PAXTON LAKE, TEXADA-ISLAND, BRITISH-COLUMBIA
ECOLOGY AND EVOLUTION OF SYMPATRIC STICKLEBACKS (GASTEROSTEUS) - EVIDENCE FOR A SPECIES-PAIR IN PAXTON LAKE, TEXADA-ISLAND, BRITISH-COLUMBIA
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DOI：
10.1139/z92-054
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发表时间：
1992-02-01
影响因子：
1.4
通讯作者：
MCPHAIL, JD
中科院分区：
文献类型：
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作者：
MCPHAIL, JD
在特克萨达岛的帕克斯顿湖中，两种形式的腹骨共存。不列颠哥伦比亚。一种形式(底栖)主要是滨海底栖觅食动物，而另一种形式(湖滨)是开放水域的浮游生物觅食者。底栖形态体型较大(标准长度可达90毫米)，身体粗壮，嘴宽，相对较少的短鳍叉，侧板和背刺的数量大大减少。大约80%的成年人没有整个骨盆带。与之形成对比的是，石斑鱼体型苗条，嘴巴狭窄，有许多长长的颧骨，侧板、背棘和骨盆带正常。在实验室杂交中，帕克斯顿湖底栖刺鱼和湖滨刺鱼的繁殖是真的，这表明它们代表着独立的基因库，而不是觅食的多态。这两种类型在形态和等位基因频率上的差异保持了20多年(约20代)的稳定，但判别函数分析表明，帕克斯顿湖约1%的成体刺鱼是杂交种。这一估计的杂交水平自1968年以来一直保持不变。等位基因频率和形态的稳定差异表明，这两种形式之间没有基因流动。然而，过去有一些关于基因流动的证据，尽管这两种形式现在表现为生物物种，但它们可能保留了交换基因的能力。这两种类型之间的遗传距离(由25个推定基因座估计)和该地区的冰后历史都表明，这种分歧是最近才出现的。
Two forms of Gasterosteus coexist in Paxton Lake on Texada Island. British Columbia. One form (benthic) is predominantly a littoral, benthic forager, whereas the other form (limnetic) is an open-water plankton feeder. The benthic form is large (up to 90 mm in standard length), with a stout body, a wide mouth, relatively few short gill rakers, and a greatly reduced number of lateral plates and dorsal spines. The entire pelvic girdle is absent in about 80% of adults. In contrast, the limnetic form is slim bodied, with a narrow mouth, numerous long gill rakers, and normal lateral plates, dorsal spines, and pelvic girdle. In laboratory crosses, Paxton Lake benthic and limnetic sticklebacks breed true and this suggests that they represent separate gene pools rather than a foraging polymorphism. The differences in morphology and allele frequencies between the two forms have remained stable for over two decades (about 20 generations), yet discriminant function analysis indicates that about 1 % of the adult sticklebacks in Paxton Lake are hybrids. This estimated level of hybridization has remained constant since 1968. The stable differences in allele frequencies and morphology suggest that there is no gene flow between the two forms. There is, however, some evidence for gene flow in the past, and although the two forms now behave as biological species, they probably retain the capacity to exchange genes. Both the genetic distance between the two forms, estimated from 25 presumptive loci, and the postglacial history of the area suggest that the divergence is recent.