GENETIC ANALYSIS OF A CHROMOSOMAL HYBRID ZONE IN THE AUSTRALIAN MORABINE GRASSHOPPERS (VANDIEMENELLA, VIATICA SPECIES GROUP)
GENETIC ANALYSIS OF A CHROMOSOMAL HYBRID ZONE IN THE AUSTRALIAN MORABINE GRASSHOPPERS (VANDIEMENELLA, VIATICA SPECIES GROUP)
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DOI：
10.1111/j.1558-5646.2008.00526.x
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发表时间：
2009-01
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影响因子：
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通讯作者：
T. Kawakami;R. Butlin;M. Adams;D. Paull;S. Cooper
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作者：
T. Kawakami;R. Butlin;M. Adams;D. Paull;S. Cooper
染色体重排是否通过为种群间的基因交换提供障碍来促进物种形成，是进化生物学中长期存在的争论之一。这个问题可以通过研究染色体不同类群间杂交带的基因流动和选择模式来解决。本文首次报道了澳大利亚袋鼠岛上morabine gras蜢vdiemenella viatica染色体小种P24（XY）和viatica17杂交带遗传结构的研究结果。染色体和11个核标记显示一个狭窄的杂交区，有强烈的连锁不平衡和杂合子缺陷，很可能是由分散和选择之间的平衡维持的。这些标记的线的宽度和位置是一致和一致的，这表明选择不可能集中在少数染色体上。相比之下，线粒体标记显示出明显更宽的倾斜，中心偏移向P24（XY）侧。我们认为，线粒体和核/染色体线的不一致以及线的整体不对称表明接触带的二次起源以及接触后该区域的潜在运动。需要使用许多遗传标记进行全基因组扫描，并对这些标记进行染色体定位，以研究染色体差异是否直接减少了二次接触后的基因流动。
Whether chromosomal rearrangements promote speciation by providing barriers to gene exchange between populations is one of the long-standing debates in evolutionary biology. This question can be addressed by studying patterns of gene flow and selection in hybrid zones between chromosomally diverse taxa. Here we present results of the first study of the genetic structure of a hybrid zone between chromosomal races of morabine grasshoppers Vandiemenella viatica, P24(XY) and viatica17, on Kangaroo Island, Australia. Chromosomal and 11 nuclear markers revealed a narrow hybrid zone with strong linkage disequilibrium and heterozygote deficits, most likely maintained by a balance between dispersal and selection. Widths and positions of clines for these markers are concordant and coincident, suggesting that selection is unlikely to be concentrated on a few chromosomes. In contrast, a mitochondrial marker showed a significantly wider cline with centre offset toward the P24(XY) side. We argue that the discordance between the mitochondrial and nuclear/chromosomal clines and overall asymmetry of the clines suggest a secondary origin of the contact zone and potential movement of the zone after contact. Genome-wide scans using many genetic markers and chromosomal mapping of these markers are needed to investigate whether chromosomal differences directly reduce gene flow after secondary contact.