Lo Nathan, Luykx Peter, Santoni Rossana, Beninati Tiziana, Bandi Claudio, Casiraghi Maurizio, Lu Wen-hua, Zakharov Evgueni V, Nalepa Christine A
School of Biological Sciences, The University of Sydney, NSW, Australia.
Zoolog Sci. 2006 Apr;23(4):393-8. doi: 10.2108/zsj.23.393.
Woodroaches of the genus Cryptocercus are subsocial and xylophagous cockroaches, distributed in North America and Asia. Studies on male chromosome number in Nearctic species have shown that diploid numbers vary from 2n=37 to 2n=47; numbers from Palearctic species were heretofore unknown. Two hypotheses have been proposed to explain the varying number of chromosomes among Nearctic species: the serial reduction hypothesis, and the parallel scenario. We performed phylogenetic analyses of the COII gene in these species and found evidence for the topology (47(45(43(39,37), which is congruent with the serial reduction hypothesis. We also determined chromosome numbers for the first time in Palearctic species, and found Cryptocercus primarius and Cryptocercus relictus to have relatively low chromosome numbers (2n=17-21) compared to their Nearctic relatives. Finally, our study determined the phylogenetic position of Cryptocercus primarius among other Asian taxa.
隐尾蠊属的木蠊是亚社会性且食木的蟑螂，分布于北美和亚洲。对新北区物种雄性染色体数目的研究表明，二倍体数目从2n = 37到2n = 47不等；此前尚不清楚古北区物种的染色体数目。已提出两种假说来解释新北区物种间染色体数目的差异：连续减少假说和平行假说。我们对这些物种的细胞色素氧化酶亚基II（COII）基因进行了系统发育分析，发现了拓扑结构（47(45(43(39,37))的证据，这与连续减少假说一致。我们还首次确定了古北区物种的染色体数目，发现与它们的新北区近亲相比，原隐尾蠊和残遗隐尾蠊的染色体数目相对较低（2n = 17 - 21）。最后，我们的研究确定了原隐尾蠊在其他亚洲分类群中的系统发育位置。
