Reprogen, Faculty of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia.
BMC Genet. 2011 Aug 19;12:72. doi: 10.1186/1471-2156-12-72.
The tammar wallaby, Macropus eugenii, a small kangaroo used for decades for studies of reproduction and metabolism, is the model Australian marsupial for genome sequencing and genetic investigations. The production of a more comprehensive cytogenetically-anchored genetic linkage map will significantly contribute to the deciphering of the tammar wallaby genome. It has great value as a resource to identify novel genes and for comparative studies, and is vital for the ongoing genome sequence assembly and gene ordering in this species.
A second-generation anchored tammar wallaby genetic linkage map has been constructed based on a total of 148 loci. The linkage map contains the original 64 loci included in the first-generation map, plus an additional 84 microsatellite loci that were chosen specifically to increase coverage and assist with the anchoring and orientation of linkage groups to chromosomes. These additional loci were derived from (a) sequenced BAC clones that had been previously mapped to tammar wallaby chromosomes by fluorescence in situ hybridization (FISH), (b) End sequence from BACs subsequently FISH-mapped to tammar wallaby chromosomes, and (c) tammar wallaby genes orthologous to opossum genes predicted to fill gaps in the tammar wallaby linkage map as well as three X-linked markers from a published study. Based on these 148 loci, eight linkage groups were formed. These linkage groups were assigned (via FISH-mapped markers) to all seven autosomes and the X chromosome. The sex-pooled map size is 1402.4 cM, which is estimated to provide 82.6% total coverage of the genome, with an average interval distance of 10.9 cM between adjacent markers. The overall ratio of female/male map length is 0.84, which is comparable to the ratio of 0.78 obtained for the first-generation map.
Construction of this second-generation genetic linkage map is a significant step towards complete coverage of the tammar wallaby genome and considerably extends that of the first-generation map. It will be a valuable resource for ongoing tammar wallaby genetic research and assembling the genome sequence. The sex-pooled map is available online at http://compldb.angis.org.au/.
塔马尔袋鼠，Macropus eugenii，是一种用于研究生殖和代谢的小型袋鼠，几十年来一直被用于基因组测序和遗传研究。制作更全面的细胞遗传学锚定遗传连锁图谱将极大地促进塔马尔袋鼠基因组的破译。它作为一种资源具有很高的价值，可以识别新基因，并进行比较研究，对于该物种正在进行的基因组序列组装和基因排序至关重要。
根据总共 148 个位点构建了第二代锚定塔马尔袋鼠遗传连锁图谱。该连锁图谱包含第一代图谱中包含的 64 个原始位点，以及另外 84 个微卫星位点，这些位点是专门选择的，旨在增加覆盖范围，并有助于将连锁群锚定和定向到染色体上。这些额外的位点来源于 (a) 通过荧光原位杂交 (FISH) 先前已映射到塔马尔袋鼠染色体的测序 BAC 克隆，(b) 随后 FISH 映射到塔马尔袋鼠染色体的 BAC 末端序列，以及 (c) 与负鼠基因同源的塔马尔袋鼠基因，预测这些基因将填补塔马尔袋鼠连锁图谱中的空白，以及来自已发表研究的三个 X 连锁标记。基于这 148 个位点，形成了 8 个连锁群。通过 FISH 映射标记将这些连锁群分配给所有 7 条常染色体和 X 染色体。该性合并图谱大小为 1402.4 cM，估计提供基因组总覆盖的 82.6%，相邻标记之间的平均间隔距离为 10.9 cM。总体而言，雌性/雄性图谱长度比为 0.84，与第一代图谱获得的 0.78 相似。
第二代遗传连锁图谱的构建是全面覆盖塔马尔袋鼠基因组的重要步骤，大大扩展了第一代图谱。它将成为塔马尔袋鼠遗传研究和组装基因组序列的宝贵资源。性合并图谱可在 http://compldb.angis.org.au/ 在线获取。
