Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Chromosome Res. 2009;17(7):873-82. doi: 10.1007/s10577-009-9078-2. Epub 2009 Sep 30.
The approximately 42 Mbp assembled genome sequence for the choanoflagellate Monosiga brevicollis reveals that most of the large scaffolds of 300-2,600 kb represent entire chromosomes or chromosome arms. Telomeres are partially assembled at the termini of 37 scaffolds, while another 43 scaffolds end in telomere-associated regions containing distinctive gene sets. Potential centromeric regions were identified on 39 scaffolds. Together, these observations suggest a karyotype of approximately 40 metacentric and submetacentric chromosomes averaging 1 Mbp in size. Genes encoding RecQ family DNA helicases, along with ankyrin-domain proteins and serine/threonine kinases, are associated with most telomeres, a feature shared with some fungi. This telomere-linked helicase gene arrangement might be ancestral to both fungi and choanoflagellates in the super-kingdom Opisthokonta; however, the great lability of telomere architecture suggests that it could also be a convergent feature.
约 42 Mbp 组装的有孔虫 Monosiga brevicollis 基因组序列显示，大多数 300-2600 kb 的大支架代表整个染色体或染色体臂。端粒在 37 个支架的末端部分组装，而另外 43 个支架以含有独特基因集的端粒相关区域结束。在 39 个支架上鉴定出潜在的着丝粒区域。总的来说，这些观察结果表明，大约有 40 个着丝粒和亚着丝粒染色体，平均大小为 1 Mbp。与大多数端粒相关的 RecQ 家族 DNA 解旋酶基因，以及锚蛋白域蛋白和丝氨酸/苏氨酸激酶基因，与一些真菌共享这一特征。这种与端粒相连的解旋酶基因排列可能是后生动物超界真菌和有孔虫的祖先进化特征；然而，端粒结构的巨大不稳定性表明，它也可能是一个趋同特征。
