Department of Genetics, Wrocław University of Environmental and Life Sciences, Kożuchowska 7, 51-631 Wrocław, Poland.
Department of Epizootiology and Clinic of Bird and Exotic Animals, Wrocław University of Environmental and Life Sciences, pl. Grunwaldzki 4, 550-366 Wroclaw, Poland.
Genes (Basel). 2021 Jun 7;12(6):878. doi: 10.3390/genes12060878.
Sexing of birds is indispensable for scientific, breeding and conservation programs but is difficult in many species and is particularly problematic in the case of nestlings showing no sexual dimorphism. Most useful and efficient methods of sex determination are based on unique features of the Z and W sex chromosomes detected via PCR to distinguish males (ZZ) and females (ZW). During the last twenty-five years researchers searched for the universal marker capable of sexing a maximally wide spectrum of species in a single PCR assay. We screened the phylogenetically representative set of 135 Psittaciformes species including 59 species sexed for the first time. Two known (P2P8, CHD1iA) PCR markers and four additional W/Z polymorphisms (CHD1iE, CHD1i16, CHD1i9 and NIPBLi16) located within the Chromo Helicase DNA binding CHD1 or the Nipped-B homolog NIPBL genes were applied. We present the electrophoretic patterns obtained for the PCR products of the analyzed markers including most typical and atypical patterns allowing sex determination, as well as those obtained when the given marker failed in sexing. Technical aspects of molecular sex determination are discussed: the optimization of amplification conditions, direct PCR and potential misinterpretations. A truly universal marker has not been found, and therefore, we propose a sexing strategy based on multiple CHD1i16, NIPBLi16, CHD1i9 and CHD1iE markers. This new strategy confirms the sex of a given bird with at least two markers detecting independent Z/W polymorphisms, reduces the number of necessary PCR reactions and minimizes the risk of sex misidentification.
鸟类的性别鉴定对于科学研究、繁殖和保护计划是必不可少的，但在许多物种中都很困难，尤其是在幼鸟没有性别二态性的情况下。最有用和有效的性别鉴定方法是基于通过 PCR 检测到的 Z 和 W 性染色体的独特特征，以区分雄性（ZZ）和雌性（ZW）。在过去的二十五年中，研究人员一直在寻找一种通用的标记物，能够在单次 PCR 检测中对最大范围的物种进行性别鉴定。我们筛选了 135 种鹦鹉类物种的系统发育代表组，其中包括 59 种首次进行性别的物种。应用了两个已知的（P2P8、CHD1iA）PCR 标记物和另外四个位于 Chromo Helicase DNA 结合 CHD1 或 Nipped-B 同源物 NIPBL 基因内的 W/Z 多态性（CHD1iE、CHD1i16、CHD1i9 和 NIPBLi16）。我们展示了分析标记物的 PCR 产物的电泳图谱，包括最典型和非典型的可用于性别鉴定的图谱，以及在给定标记物无法进行性别鉴定时获得的图谱。讨论了分子性别鉴定的技术方面：扩增条件的优化、直接 PCR 和潜在的误解。还没有找到真正通用的标记物，因此，我们提出了一种基于多个 CHD1i16、NIPBLi16、CHD1i9 和 CHD1iE 标记物的性别鉴定策略。这种新策略通过检测独立的 Z/W 多态性来确认给定鸟类的性别，减少了必要的 PCR 反应次数，并最大程度地降低了性别误识别的风险。
