Ouchia-Benissad Siham, Ladjali-Mohammedi Kafia
University of Sciences and Technology Houari Boumediene, Faculty of Biological Sciences, LBCM lab., Team: Genetics of Development. USTHB, PO box 32 El-Alia, Bab-Ezzouar, 16110 Algiers, Algeria.
Comp Cytogenet. 2018 Jun 4;12(2):171-199. doi: 10.3897/CompCytogen.v12i2.23743. eCollection 2018.
The development of avian cytogenetics is significantly behind that of mammals. In fact, since the advent of cytogenetic techniques, fewer than 1500 karyotypes have been established. The Barbary partridge Bonnaterre, 1790 is a bird of economic interest but its genome has not been studied so far. This species is endemic to North Africa and globally declining. The Chukar partridge Gray, 1830 is an introduced species which shares the same habitat area as the Barbary partridge and so there could be introgressive hybridisation. A cytogenetic study has been initiated in order to contribute to the Barbary partridge and the Chukar partridge genome analyses. The GTG, RBG and RHG-banded karyotypes of these species have been described. Primary fibroblast cell lines obtained from embryos were harvested after simple and double thymidine synchronisation. The first eight autosomal pairs and Z sex chromosome have been described at high resolution and compared to those of the domestic fowl Linnaeus, 1758. The diploid number was established as 2n = 78 for both partridges, as well as for most species belonging to the Galliformes order, underlying the stability of chromosome number in avian karyotypes. Wide homologies were observed for macrochromosomes and gonosome except for chromosome 4, 7, 8 and Z which present differences in morphology and/or banding pattern. Neocentromere occurrence was suggested for both partridges chromosome 4 with an assumed paracentric inversion in the Chukar partridge chromosome 4. Terminal inversion in the long arm of the Barbary partridge chromosome Z was also found. These rearrangements confirm that the avian karyotypes structure is conserved interchromosomally, but not at the intrachromosomal scale.
鸟类细胞遗传学的发展明显落后于哺乳动物。事实上，自细胞遗传学技术问世以来，已确定的核型不到1500种。巴巴里鹧鸪（Bonnaterre，1790年）是一种具有经济价值的鸟类，但其基因组迄今尚未得到研究。该物种原产于北非，数量在全球范围内呈下降趋势。石鸡（Gray，1830年）是一种引入物种，与巴巴里鹧鸪共享相同的栖息地，因此可能存在渐渗杂交。为了有助于对巴巴里鹧鸪和石鸡的基因组进行分析，已经启动了一项细胞遗传学研究。已经描述了这些物种的GTG、RBG和RHG带型核型。从胚胎中获得的原代成纤维细胞系在经过简单和双重胸腺嘧啶核苷同步化后进行收获。已经对前八对常染色体和Z性染色体进行了高分辨率描述，并与家鸡（Linnaeus，1758年）的进行了比较。两种鹧鸪以及鸡形目大多数物种的二倍体数均确定为2n = 78，这表明鸟类核型中染色体数目的稳定性。除了4号、7号、8号染色体和Z染色体在形态和/或带型模式上存在差异外，在常染色体和性染色体上观察到广泛的同源性。有人认为两种鹧鸪的4号染色体都出现了新着丝粒，石鸡的4号染色体可能存在臂内倒位。还发现了巴巴里鹧鸪Z染色体长臂的末端倒位。这些重排证实，鸟类核型结构在染色体间是保守的，但在染色体内尺度上并非如此。
