Inferences from a rapidly moving hybrid zone
Inferences from a rapidly moving hybrid zone
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DOI：
10.1111/j.0014-3820.2002.tb01385.x
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发表时间：
2002-04-01
期刊：
影响因子：
3.3
通讯作者：
Mallett, T
中科院分区：
文献类型：
--
作者：
Dasmahapatra, KK;Blum, MJ;Mallett, T
Anartia法蒂玛和Anartia amathea（鳞翅目：蛱蝶科）是姐妹分类群，其范围在巴拿马东部的一个狭窄的杂交区毗邻。在该区域的中心，杂交种是丰富的，虽然偏离哈代-温伯格和连锁不平衡是强大的，部分原因是竞争性交配。我们测量了四个翅膀颜色图案的字符，三个等位酶基因座，和线粒体单倍型在整个区域的差异。翅型、等位酶和线粒体的倾斜是一致的（即，具有相同的位置）和一致的（即，所有标记具有相似的渐变形状，约28公里宽）。重复的样品表明，混合带已向东移动，在过去的20年中，平均每年2.5公里，伴随着相当的运动的mtDNA渐变群。没有渐渗的mtDNA单倍型被发现在“唤醒”的移动渐变群，可能是一个中性标记。1994年和2000年之间的一致性形态和mtDNA的倾斜，尽管杂交区运动，表明线粒体基因组和核基因座之间的强上位性。无性系运动主要是通过纯法蒂玛移民到amathea种群实现的;杂交种几乎没有影响，并且可能被更适合的纯法蒂玛基因型所击败。如果7- 19km.gen（-1/2）的随机扩散与A的竞争优势相结合，则可以解释这种运动。2- 5%的法蒂玛基因组。混合区运动相当于赖特的第三阶段的转移平衡。混合带运动在过去很少被认为是可能的，但我们的研究结果表明，它可能是更重要的地理和进化比一般意识到的。
Anartia fatima and Anartia amathea (Lepidoptera: Nymphalidae) are sister taxa whose ranges abut in a narrow hybrid zone in eastern Panama. At the center of the zone, hybrids are abundant, although deviations from Hardy-Weinberg and linkage disequilibria are strong, due in part to assortative mating. We measured differences across the zone in four wing color-pattern characters, three allozyme loci, and mitochondrial haplotype. Wing pattern, allozyme, and mitochondrial clines were coincident (i.e., had the same positions) and concordant (i.e., all markers had similar cline shapes, about 28 km wide). Repeated samples demonstrated that the hybrid zone has been moving eastwards at an average rate of 2.5 km/year over the past 20 years, accompanied by an equivalent movement of the mtDNA cline. No introgression of mtDNA haplotypes were found in the "wake" of the moving cline, as might be expected for a neutral marker. The concordance of morphological and mtDNA clines between 1994 and 2000, in spite of hybrid zone movement, suggests strong epistasis between the mitochondrial genome and nuclear loci. Cline movement is achieved mainly by pure fatima immigrating into amathea populations; hybrids had little effect, and were presumably outcompeted by fitter pure fatima genotypes. This movement can be explained if random dispersal of 7-19 km.gen(-1/2) is coupled with a competitive advantage to A. fatima genomes of 2-5%. Hybrid zone motion is equivalent to Phase III of Wright's shifting balance. Hybrid zone movement has rarely been considered likely in the past, but our results show that it may be more important in biogeography and evolution than generally realized.