Martinsen E S, Paperna I, Schall J J
Department of Biology, University of Vermont, Burlington, Vermont 05405, USA.
Parasitology. 2006 Sep;133(Pt 3):279-88. doi: 10.1017/S0031182006000424. Epub 2006 Jun 2.
More than 200 species of avian Haemosporidia (genera Plasmodium, Haemoproteus, and Leucocytozoon) have been described based primarily on morphological characters seen in blood smears. Recent molecular studies, however, suggest that such methods may mask a substantial cryptic diversity of avian haemosporidians. We surveyed the haemosporidians of birds sampled at 1 site in Israel. Parasites were identified to species based on morphology, and a segment of the parasite's cytochrome b gene was sequenced. We compared 3 species concepts: morphological, genetic, and phylogenetic. Fifteen morphological species were present. Morphological species that occurred once within our dataset were associated with a unique gene sequence, displayed large genetic divergence from other morphological species, and were not contained within clades of morphological species that occurred more than once. With only 1 exception, morphological species that were identified from multiple bird hosts presented identical sequences for all infections, or differed by few synonymous substitutions, and were monophyletic for all phylogenetic analyses. Only the morphological species Haemoproteus belopolskyi did not follow this trend, falling instead into at least 2 genetically distant clades. Thus, except for H. belopolskyi, parasites identified to species by morphology were supported by both the genetic and phylogenetic species concepts.
基于在血涂片上观察到的形态特征，已描述了200多种禽血孢子虫（疟原虫属、血变虫属和白细胞虫属）。然而，最近的分子研究表明，这些方法可能掩盖了禽血孢子虫大量的隐性多样性。我们调查了在以色列一个地点采集的鸟类的血孢子虫。根据形态将寄生虫鉴定到种，并对寄生虫的细胞色素b基因片段进行测序。我们比较了三种物种概念：形态学概念、遗传学概念和系统发育学概念。存在15个形态学种。在我们的数据集中仅出现一次的形态学种与独特的基因序列相关，与其他形态学种表现出较大的遗传差异，并且不包含在多次出现的形态学种的进化枝内。除了1个例外，从多个鸟类宿主中鉴定出的形态学种在所有感染中都呈现相同的序列，或仅相差少数同义替换，并且在所有系统发育分析中都是单系的。只有形态学种伯氏血变虫不遵循这一趋势，而是至少落入2个遗传距离较远的进化枝中。因此，除了伯氏血变虫外，通过形态学鉴定到种的寄生虫得到了遗传学和系统发育学物种概念的支持。
