Matsubara Kazumi, Uno Yoshinobu, Srikulnath Kornsorn, Matsuda Yoichi, Miller Emily, Olsson Mats
From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson).
J Hered. 2015 Nov-Dec;106(6):753-7. doi: 10.1093/jhered/esv083. Epub 2015 Oct 12.
Telomeres are repeat (TTAGGG) n sequences that form terminal ends of chromosomes and have several functions, such as protecting the coding DNA from erosion at mitosis. Due to chromosomal rearrangements through evolutionary history (e.g., inversions and fusions), telomeric sequences are also found between the centromere and the terminal ends (i.e., at interstitial telomeric sites, ITSs). ITS telomere sequences have been implicated in heritable disease caused by genomic instability of ITS polymorphic variants, both with respect to copy number and sequence. In the sand lizard (Lacerta agilis), we have shown that telomere length is predictive of lifetime fitness in females but not males. To assess whether this sex specific fitness effect could be traced to ITSs differences, we mapped (TTAGGG) n sequences using fluorescence in situ hybridization in fibroblast cells cultured from 4 specimens of known sex. No ITSs could be found on autosomes in either sex. However, females have heterogametic sex chromosomes in sand lizards (ZW, 2n = 38) and the female W chromosome showed degeneration and remarkable (TTAGGG) n amplification, which was absent in the Z chromosomes. This work warrants further research on sex chromosome content, in particular of the degenerate W chromosome, and links to female fitness in sand lizards.
端粒是重复序列（TTAGGG）n，它构成染色体的末端并具有多种功能，比如在有丝分裂时保护编码DNA免受侵蚀。由于在进化历史中发生染色体重排（例如倒位和融合），端粒序列也存在于着丝粒和末端之间（即在间质端粒位点，ITSs）。ITS端粒序列与由ITS多态变体的基因组不稳定性导致的遗传性疾病有关，这涉及拷贝数和序列两方面。在沙蜥（Lacerta agilis）中，我们已经表明端粒长度可预测雌性而非雄性的终生适应性。为了评估这种性别特异性适应性效应是否可追溯到ITSs差异，我们使用荧光原位杂交技术对从4个已知性别的标本培养的成纤维细胞中的（TTAGGG）n序列进行了定位。在任何一个性别的常染色体上均未发现ITSs。然而，沙蜥雌性具有异型性染色体（ZW，2n = 38），并且雌性W染色体显示出退化和显著的（TTAGGG）n扩增，而Z染色体上则没有。这项工作值得进一步研究性染色体的组成，特别是退化的W染色体，并探究其与沙蜥雌性适应性的联系。
