Urton J R, McCann S R, Peichel C L
Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA.
Cytogenet Genome Res. 2011;135(2):150-9. doi: 10.1159/000331232. Epub 2011 Sep 13.
The stickleback family (Gasterosteidae) of fish is less than 40 million years old, yet stickleback species have diverged in both diploid chromosome number (2n) and morphology. We used comparative fluorescence in situ hybridization (FISH) on 2 stickleback species, Gasterosteus aculeatus (2n = 42) and Apeltes quadracus (2n = 46), to ascertain the types of chromosome rearrangements that differentiate these species. The A. quadracus karyotype contains more acrocentric and telocentric chromosomes than the G. aculeatus karyotype. By using bacterial artificial chromosome probes from G. aculeatus in our FISH screen, we found that 6 pericentric inversions and 2 chromosome fusions/fissions are responsible for the greater number of acrocentric and telocentric chromosomes in A. quadracus. While most populations of G. aculeatus have an XX/XY sex chromosome system, A. quadracus has a ZZ/ZW sex chromosome system, as previously reported. However, we discovered that a population of A. quadracus from Connecticut lacks heteromorphic sex chromosomes, providing evidence for unexpected sex chromosome diversity in this species.
刺鱼科鱼类的历史不到4000万年，但刺鱼物种在二倍体染色体数目（2n）和形态上都已发生了分化。我们对两种刺鱼，即三刺鱼（2n = 42）和四刺鱼（2n = 46）进行了比较荧光原位杂交（FISH），以确定区分这些物种的染色体重排类型。四刺鱼的核型比三刺鱼的核型含有更多的近端着丝粒染色体和端着丝粒染色体。通过在我们的FISH筛选中使用来自三刺鱼的细菌人工染色体探针，我们发现6次臂间倒位和2次染色体融合/裂变导致了四刺鱼中近端着丝粒染色体和端着丝粒染色体数量的增加。如先前报道的那样，虽然大多数三刺鱼种群具有XX/XY性染色体系统，但四刺鱼具有ZZ/ZW性染色体系统。然而，我们发现来自康涅狄格州的一群四刺鱼缺乏异型性染色体，这为该物种中意想不到的性染色体多样性提供了证据。
