Jeffery Nicholas W, Oliveira Ivo S, Gregory T Ryan, Rowell David M, Mayer Georg
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada.
Genetica. 2012 Dec;140(10-12):497-504. doi: 10.1007/s10709-013-9698-5. Epub 2013 Jan 11.
The Onychophora (velvet worms) represents a small group of invertebrates (~180 valid species), which is commonly united with Tardigrada and Arthropoda in a clade called Panarthropoda. As with the majority of invertebrate taxa, genome size data are very limited for the Onychophora, with only one previously published estimate. Here we use both flow cytometry and Feulgen image analysis densitometry to provide genome size estimates for seven species of velvet worms from both major subgroups, Peripatidae and Peripatopsidae, along with karyotype data for each species. Genome sizes in these species range from roughly 5-19 pg, with densitometric estimates being slightly larger than those obtained by flow cytometry for all species. Chromosome numbers range from 2n = 8 to 2n = 54. No relationship is evident between genome size, chromosome number, or reproductive mode. Various avenues for future genomic research are presented based on these results.
有爪动物（天鹅绒虫）是一小类无脊椎动物（约180个有效物种），通常与缓步动物门和节肢动物门一起归入泛节肢动物这一进化枝。与大多数无脊椎动物类群一样，有爪动物的基因组大小数据非常有限，此前仅有一项公开的估计。在此，我们使用流式细胞术和福尔根图像分析密度测定法，对主要亚群栉蚕科和山蛩虫科的七种天鹅绒虫的基因组大小进行估计，并提供每个物种的核型数据。这些物种的基因组大小范围约为5 - 19皮克，密度测定估计值略大于所有物种通过流式细胞术获得的估计值。染色体数目范围从2n = 8到2n = 54。基因组大小、染色体数目或繁殖方式之间没有明显的关系。基于这些结果，我们提出了未来基因组研究的各种途径。
