Bird chromosomes, which have been investigated scientifically for more than a century, present a number of unique features. In general, bird karyotypes have a high diploid number (2n) of typically around 80 chromosomes that are divided into macro- and microchromosomes. In recent decades, FISH studies using whole chromosome painting probes have shown that the macrochromosomes evolved through both inter- and intrachromosomal rearrangements. However, chromosome painting data are available for only a few bird species, which hinders a more systematic approach to the understanding of the evolutionary history of the enigmatic bird karyotype. Thus, we decided to create an innovative database through compilation of the cytogenetic data available for birds, including chromosome numbers and the results of chromosome painting with chicken (Gallus gallus) probes. The data were obtained through an extensive literature review, which focused on cytogenetic studies published up to 2019. In the first version of the “Bird Chromosome Database (BCD)” (https://sites.unipampa.edu.br/birdchromosomedatabase) we have compiled data on the chromosome numbers of 1,067 bird species and chromosome painting data on 96 species. We found considerable variation in the diploid numbers, which ranged from 40 to 142, although most (around 50%) of the species studied up to now have between 78 and 82 chromosomes. Despite its importance for cytogenetic research, chromosome painting has been applied to less than 1% of all bird species. The BCD will enable researchers to identify the main knowledge gaps in bird cytogenetics, including the most under-sampled groups, and make inferences on chromosomal homologies in phylogenetic studies.

中文翻译：

---

鸟类染色体数据库简介：鸟类细胞遗传学研究概述

经过一个多世纪的科学研究，鸟类染色体呈现出许多独特的特征。一般而言，鸟类核型具有高二倍体数 (2n)，通常约为 80 条染色体，分为大染色体和小染色体。近几十年来，使用全染色体染色探针的 FISH 研究表明，大染色体通过染色体间和染色体内的重排进化。然而，染色体绘画数据仅适用于少数鸟类，这阻碍了对神秘鸟类核型进化历史的理解的更系统方法。因此，我们决定通过汇编鸟类可用的细胞遗传学数据来创建一个创新的数据库，包括染色体数目和用鸡（Gallus gallus）探针进行染色体染色的结果。这些数据是通过广泛的文献综述获得的，重点是截至 2019 年发表的细胞遗传学研究。在“鸟类染色体数据库（BCD）”（https://sites.unipampa.edu.br/birdchromosomedatabase）的第一版中，我们编制了1067种鸟类的染色体数据和96种鸟类的染色体涂色数据。我们发现二倍体数量有相当大的变化，范围从 40 到 142，尽管迄今为止研究的大多数物种（约 50%）具有 78 到 82 条染色体。尽管它对细胞遗传学研究很重要，但染色体着色已应用于不到 1% 的所有鸟类物种。BCD 将使研究人员能够确定鸟类细胞遗传学的主要知识差距，