Genomic Medicine Institute, Cleveland Clinic, 9500 Euclid Ave,/NE50, Cleveland, OH 44195, USA.
Malar J. 2013 Feb 14;12:64. doi: 10.1186/1475-2875-12-64.
Members of the Anopheles punctulatus group (AP group) are the primary vectors of human malaria in Papua New Guinea. The AP group includes 13 sibling species, most of them morphologically indistinguishable. Understanding why only certain species are able to transmit malaria requires a better comprehension of their evolutionary history. In particular, understanding relationships and divergence times among Anopheles species may enable assessing how malaria-related traits (e.g. blood feeding behaviours, vector competence) have evolved.
DNA sequences of 14 mitochondrial (mt) genomes from five AP sibling species and two species of the Anopheles dirus complex of Southeast Asia were sequenced. DNA sequences from all concatenated protein coding genes (10,770 bp) were then analysed using a Bayesian approach to reconstruct phylogenetic relationships and date the divergence of the AP sibling species.
Phylogenetic reconstruction using the concatenated DNA sequence of all mitochondrial protein coding genes indicates that the ancestors of the AP group arrived in Papua New Guinea 25 to 54 million years ago and rapidly diverged to form the current sibling species.
Through evaluation of newly described mt genome sequences, this study has revealed a divergence among members of the AP group in Papua New Guinea that would significantly predate the arrival of humans in this region, 50 thousand years ago. The divergence observed among the mtDNA sequences studied here may have resulted from reproductive isolation during historical changes in sea-level through glacial minima and maxima. This leads to a hypothesis that the AP sibling species have evolved independently for potentially thousands of generations. This suggests that the evolution of many phenotypes, such as insecticide resistance will arise independently in each of the AP sibling species studied here.
按蚊 punctulatus 组（AP 组）的成员是巴布亚新几内亚人类疟疾的主要传播媒介。AP 组包括 13 个姐妹种，其中大多数在形态上无法区分。要了解为什么只有某些物种能够传播疟疾，就需要更好地了解它们的进化历史。特别是，了解按蚊种之间的关系和分化时间可以评估与疟疾相关的特征（例如吸血行为、媒介能力）是如何进化的。
对来自五个 AP 姐妹种和东南亚安蚊 dirus 复合体的两个种的 14 个线粒体（mt）基因组的 DNA 序列进行了测序。然后，使用贝叶斯方法对所有串联的蛋白质编码基因（10770bp）的 DNA 序列进行分析，以重建系统发育关系并确定 AP 姐妹种的分化时间。
使用所有线粒体蛋白质编码基因的串联 DNA 序列进行的系统发育重建表明，AP 组的祖先在 2500 万至 5400 万年前到达巴布亚新几内亚，并迅速分化形成目前的姐妹种。
通过评估新描述的 mt 基因组序列，本研究揭示了在巴布亚新几内亚，AP 组成员之间的分化发生在人类到达该地区的 5 万年前，明显更早。这里研究的 mtDNA 序列之间观察到的分化可能是由于海平面在冰期最小和最大期间发生变化导致的生殖隔离所致。这导致了一个假设，即 AP 姐妹种已经独立进化了可能数千代。这表明，这里研究的 AP 姐妹种中的许多表型，如抗药性，将独立进化。
