Supplementary Material for: Cytogenetic Mapping of Cattle BAC Probes for the Hypothetical Ancestral Karyotype of the Family Cervidae

Cervids are characterized by their greatest karyotypic diversity among mammals. A great diversity of chromosome numbers in notably similar morphological groups leads to the existence of several complexes of cryptic species and taxonomic uncertainties. Some deer lineages, such as those of Neotropical deer, stand out for a rapid chromosomal reorganization and intraspecific chromosome polymorphisms, which have not been properly explored yet. For that reason, we contribute to the study of deer karyotype diversity and taxonomy by producing and characterizing new molecular cytogenetic markers for the gray brocket deer (Subulo gouazoubira), a deer species that retained the hypothetical ancestral karyotype of Cervidae. We used bacterial artificial chromosome (BAC) clones derived from the cattle genome (Bos taurus) as markers, which were hybridized on S. gouazoubira metaphase chromosomes. In total, we mapped 108 markers, encompassing all gray brocket deer chromosomes, except the Y chromosome. The detailed analysis of fluorescent in situ hybridization results showed 6 fissions and 1 fusion as interchromosomal rearrangements that have separated cattle and gray brocket deer karyotypes. Each group of BAC probes derived from bovine chromosome pairs 1, 2, 5, 6, 8, and 9 showed hybridization signals on 2 different chromosomes, while pairs 28 and 26 are fused in tandem in a single acrocentric chromosome in S. gouazoubira. Furthermore, the BAC markers detected the occurrence of intrachromosomal rearrangements in the S. gouazoubira chromosomes homologous to pair 1 and the X chromosome of cattle. We present a karyotypic map of the 108 new markers, which will be of great importance for future karyotypic evolution studies in cervids and, consequently, help in their conservation and taxonomy resolution.

鹿科（Cervidae）动物是哺乳动物中核型多样性最为丰富的类群。在形态学上极为相似的类群中，染色体数目存在极大差异，这导致了多个隐存种复合群的出现以及分类学上的诸多不确定之处。部分鹿类支系——如新热带鹿类——因其快速的染色体重组和种内染色体多态性而备受关注，但相关研究尚未得到充分探索。有鉴于此，本研究针对灰短角鹿（*Subulo gouazoubira*，一种保留了鹿科假想祖先核型的鹿类物种）开发并鉴定了全新的分子细胞遗传学标记，以期为鹿类核型多样性与分类学研究提供助力。本研究以牛（*Bos taurus*）基因组来源的细菌人工染色体（bacterial artificial chromosome, BAC）克隆作为标记，将其杂交至灰短角鹿的中期染色体上。最终共定位了108个标记，覆盖了灰短角鹿除Y染色体外的所有染色体。对荧光原位杂交（fluorescent in situ hybridization, FISH）结果的详细分析显示，牛与灰短角鹿的核型之间存在6次染色体断裂和1次染色体融合这两类染色体间重排事件。源自牛1、2、5、6、8、9号染色体的每组BAC探针，均在两条不同的染色体上产生了杂交信号；而牛28号与26号染色体在灰短角鹿中以串联方式融合为一条近端着丝粒染色体。此外，通过BAC标记还发现，灰短角鹿中与牛1号染色体及X染色体同源的染色体发生了染色体内重排。本研究构建了包含这108个全新标记的核型图谱，该图谱将为未来鹿科动物核型进化研究提供重要支撑，进而助力鹿类物种的保护与分类学问题的解决。