Huttunen Susanna, Vieira Jorge, Hoikkala Anneli
Department of Biology, University of Oulu, Finland.
Genetica. 2002 Jun;115(2):159-67. doi: 10.1023/a:1020102602268.
Genes found to affect male courtship song characters in Drosophila melanogaster are good candidates when tracing genes responsible for species-specific songs in other Drosophila species. It has previously been shown that Thr-Gly repeat length variation at the period gene affects song traits in D. melanogaster, which gives the repetitive regions a special interest. In this work, we have characterised the patterns of nucleotide variation for gene regions containing two Gly and one Gln-Ala repeat in another D. melanogaster song gene, no-on-transient A, in D. virilis group species. The levels of nucleotide variability in D. virilis nonA were similar to those found for other genes of the species, and the gene sequences showed no signs of deviation from neutrality. The Gly 2 repeat preceding the central domain of the gene exhibited length variation, which did not, however, correlate with song variation either within D. virilis or between the species of D. virilis group. The Gly 3 repeat located on the other side of the central domain showed amino acid divergence parallel to the consensus phylogeny of the D. virilis group species. The species of the virilis subgroup having Asn after the first three glycines in this repeat have simple songs with no species-specificity, while the species of the montana subgroup having two Gly or Asn-Ser in this site have unique courtship songs. Amino acid differences between the species in this repeat may, however, reflect species phylogeny rather than have an effect on song divergence per se.
在追踪其他果蝇物种中负责物种特异性歌声的基因时，在黑腹果蝇中发现的影响雄性求偶歌声特征的基因是很好的候选基因。此前已经表明，周期基因处的苏氨酸 - 甘氨酸重复长度变异会影响黑腹果蝇的歌声特征，这使得这些重复区域具有特殊的研究价值。在这项工作中，我们已经对包含两个甘氨酸和一个谷氨酰胺 - 丙氨酸重复的基因区域的核苷酸变异模式进行了表征，该区域位于另一个黑腹果蝇歌声基因——无瞬变A基因中，存在于果蝇属物种中。果蝇属物种中非A基因的核苷酸变异水平与该物种其他基因的变异水平相似，并且基因序列没有显示出偏离中性的迹象。该基因中央结构域之前的甘氨酸2重复序列表现出长度变异，然而，这种变异在果蝇属内部或果蝇属物种之间都与歌声变异无关。位于中央结构域另一侧的甘氨酸3重复序列显示出与果蝇属物种的系统发育一致的氨基酸分歧。在这个重复序列中前三个甘氨酸之后为天冬酰胺的果蝇属亚组物种具有简单的歌声，没有物种特异性，而在这个位点具有两个甘氨酸或天冬酰胺 - 丝氨酸的蒙大拿亚组物种具有独特的求偶歌声。然而，这个重复序列中物种之间的氨基酸差异可能反映的是物种的系统发育，而不是对歌声差异本身产生影响。
