Origin and Evolution of temperate Drosophila

温带果蝇的起源和进化

基本信息

批准号：
10836003
负责人：
KIMURA Masahito
金额：
$ 1.98万
依托单位：
HOKKAIDO UNVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Temperate drosophilids have been assumed to have originated from tropics or subtropics. The present study suggests that fungus-and herbage-feeders are advantageous to colonize temperate regions. In the Drosophila melanogaster species group of which members are fruit-feeders, some members of the takahashii and montium subgroups have succeeded to colonize temperate regions. The present molecular phylogenetic study suggests that at least the temperate members of the montium subgroup have originated from subtropical highlands. The temperate and subtropical highland species were able to grow at moderately low temperatures. This ability may be preadaptation to colonize temperate regions. However, the subtropical highland species did not have diapause and coldtolerance as well as the subtropical lowland species. Therefore, it is considered that a large genetic changes are required for the subtropical highland species to adapt to temperate climates. Diapause of temperate species is known to be critical to control life cycles and acquire cold tolerance. The present result suggests that diapause is important to acquire resistance to microorganisms. Most of these temperate species are multivoltine and enter diapause at short daylengths in autumn. On the other hand, D.alpina and D.moriwakii were univoltine and had long-day diapause in addition to short-day diapause. Since they have short-day diapause, their ancestors are assumed to be multivoltine and become univoltine through acquisition of long-day diapause.

温带果蝇被认为起源于热带或亚热带。目前的研究表明，以真菌和牧草为食的动物有利于在温带地区定居。在以水果为食的果蝇物种组中，高桥亚组和蒙特亚组的一些成员已经成功地在温带地区定居。目前的分子系统发育研究表明，至少 montium 亚群的温带成员起源于亚热带高地。温带和亚热带高原物种能够在中等低温下生长。这种能力可能是对温带地区殖民的预适应。然而，亚热带高地物种不像亚热带低地物种那样具有滞育和耐寒性。因此，认为亚热带高原物种需要进行较大的遗传改变才能适应温带气候。众所周知，温带物种的滞育对于控制生命周期和获得耐寒性至关重要。目前的结果表明滞育对于获得微生物抗性很重要。大多数这些温带物种都是多性的，并在秋季短日照时进入滞育。另一方面，D.alpina 和 D.moriwakii 是单性的，除了短日滞育之外，还具有长日照滞育。由于它们具有短日照滞育，因此它们的祖先被认为是多化性的，并通过获得长日照滞育而变成单化性。