Fanara J J, Hasson E, Rodríguez C
GIBE, Departmento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
Hereditas. 1997;126(3):233-7. doi: 10.1111/j.1601-5223.1997.00233.x.
Previous works in a colonized and an original population of Drosophila buzzatii have shown a consistent relationship between the inversion polymorphism and thorax length, a measure of body size. However, the populations studied in those reports share a close genealogical relationship as suggested by several lines of evidence. In the present paper, we revisit this issue by analysing the correlation between second chromosome arrangements and thorax length in two Argentinian natural populations (Termas de Río Hondo and Arroyo Escobar) from different biogeographic areas with different host plants. Our findings are: (1) inversion frequencies were significantly different between populations; (2) the mean thorax length of flies collected in both populations was not significantly different; and (3) we obtain confirming evidence that flies carrying 2st, the ancestral gene order, have on average a smaller body size than those carrying the derived arrangements (2j and 2jz3). These results suggest that the biometrical effect of inversions on body size previously described are due to genetic differences between arrangements and not to the close historical relationship between the populations studied in previous reports.
之前对果蝇（Drosophila buzzatii）的一个定殖种群和原始种群的研究表明，倒位多态性与胸部长度（一种衡量体型的指标）之间存在稳定的关系。然而，正如几条证据线索所表明的，那些报告中所研究的种群有着密切的谱系关系。在本文中，我们通过分析来自不同生物地理区域、以不同寄主植物为食的两个阿根廷自然种群（里奥洪多温泉镇和阿罗约埃斯科瓦尔）中第二条染色体排列与胸部长度之间的相关性，重新审视了这个问题。我们的研究结果如下：（1）不同种群之间的倒位频率存在显著差异；（2）两个种群中采集到的果蝇的平均胸部长度没有显著差异；（3）我们获得了确证，即携带祖先基因顺序2st的果蝇平均体型小于携带衍生排列（2j和2jz3）的果蝇。这些结果表明，之前所描述的倒位对体型的生物统计学效应是由于排列之间的遗传差异，而不是由于之前报告中所研究的种群之间密切的历史关系。
