Duvernell D D, Aspinwall N
Department of Biology, Saint Louis University, MO 63103, USA.
Mol Ecol. 1995 Apr;4(2):173-81. doi: 10.1111/j.1365-294x.1995.tb00206.x.
The cyprinid fishes Luxilus cornutus and Luxilus chrysocephalus hybridize extensively in a zone extending through the Great Lakes region with extensive introgression of L. cornutus mtDNA occurring in populations of L. chrysocephalus south of the present hybrid zone in Ohio. Western populations of these two species occur adjacent to one another in Missouri but hybridization has never been observed. In order to determine if hybridization has occurred historically in Missouri, allopatric populations of L. chrysocephalus were analysed for mtDNA introgression. Extensive introgression of L. cornutus mtDNA was observed in most populations of L. chrysocephalus in Missouri resulting in the elimination of L. chrysocephalus mtDNA in many populations. Luxilus cornutus mtDNA in L. chrysocephalus is found approximately 300 km south of extant L. cornutus populations in Missouri. Luxilus chrysocephalus mtDNA was replaced by four unique L. cornutus mtDNA haplotypes, with one particular haplotype becoming fixed in several L. chrysocephalus populations. The pattern of introgression suggests that historically L. cornutus occupied a more southern distribution in Missouri bringing it into contact with western populations of L. chrysocephalus and resulting in a hybrid zone.
鲤科鱼类角突亮鳍鱼（Luxilus cornutus）和金黄头亮鳍鱼（Luxilus chrysocephalus）在一个贯穿五大湖地区的区域广泛杂交，在俄亥俄州当前杂交区以南的金黄头亮鳍鱼种群中出现了大量角突亮鳍鱼线粒体DNA的渐渗。这两个物种在密苏里州的西部种群彼此相邻，但从未观察到杂交现象。为了确定密苏里州历史上是否发生过杂交，对金黄头亮鳍鱼的异域种群进行了线粒体DNA渐渗分析。在密苏里州的大多数金黄头亮鳍鱼种群中观察到了角突亮鳍鱼线粒体DNA的广泛渐渗，导致许多种群中金黄头亮鳍鱼线粒体DNA被消除。在密苏里州，金黄头亮鳍鱼体内的角突亮鳍鱼线粒体DNA出现在现存角突亮鳍鱼种群以南约300公里处。金黄头亮鳍鱼的线粒体DNA被四种独特的角突亮鳍鱼线粒体DNA单倍型取代，其中一种特定的单倍型在几个金黄头亮鳍鱼种群中固定下来。渐渗模式表明，历史上角突亮鳍鱼在密苏里州的分布更偏南，使其与金黄头亮鳍鱼的西部种群接触，从而形成了一个杂交区。
