Zoology Museum, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
J Insect Sci. 2010;10:118. doi: 10.1673/031.010.11801.
Knowledge of karyotypical characteristics of a species is essential for understanding how sexually selected and sexually antagonistic traits evolve. The yellow dung fly Scathophaga stercoraria L. (Diptera: Scathophagidae) is an established model system for studies of sexual selection and sexual conflict, but karyotypical data are lacking to date. Here, the karyotype of S. stercoraria was characterized using conventional Giemsa-staining and C-banding techniques. The diploid chromosome set consists of 6 pairs of bi-armed meta- or submetacentric chromosomes. The sex chromosomes are the largest chromosomes and constitute 30% of the total length of the diploid set in females and about 25% in males. Males are the heterogametic sex, and the length of the Y chromosome is about three-quarters of that of the X chromosome. C-banding revealed that both sex chromosomes are largely heterochromatic. In contrast, in the five autosome pairs, heterochromatin is limited to narrow bands in the centromeric regions. This karyotypic information will help provide a more profound understanding of the inheritance of phenotypic variation in reproductive traits and the chromosomal locations of underlying genes.
了解物种的染色体特征对于理解性选择和性拮抗特征的进化至关重要。黄粪蝇 Scathophaga stercoraria L.（双翅目：粪蝇科）是性选择和性冲突研究的既定模式生物系统，但迄今为止缺乏染色体组型数据。本文采用常规的吉姆萨染色和 C 带技术对 S. stercoraria 的染色体组型进行了描述。二倍体染色体组由 6 对双臂近中或亚中着丝粒染色体组成。性染色体是最大的染色体，在雌性中占二倍体总长度的 30%，在雄性中占约 25%。雄性是异型性染色体，Y 染色体的长度约为 X 染色体的四分之三。C 带显示两条性染色体主要是异染色质。相比之下，在五对常染色体中，异染色质仅限于着丝粒区域的窄带。这些染色体组型信息将有助于更深入地了解生殖特征表型变异的遗传以及潜在基因的染色体位置。
