Jones C D
Department of Biology, University of Rochester, Rochester, NY 14627, USA.
Heredity (Edinb). 2004 Mar;92(3):235-41. doi: 10.1038/sj.hdy.6800401.
Drosophila sechellia, an island endemic that specializes on a single host plant, has a lower rate of egg production than its generalist sister species D. melanogaster, D. simulans, and D. mauritiana. Earlier work showed that part of this difference in egg production was due to a reduction in the number of ovarioles in D. sechellia relative to its sister species. Here, I extend this earlier work by genetically analyzing the difference in egg production between D. sechellia and D. simulans. In all, 10 genetic markers were used in several interspecific backcrosses to identify chromosome regions that affected the rate of egg production. While previously mapped factors affecting ovariole number appear to impact the rate of egg production, new, non-ovariole factors were also identified. Overall, the difference in egg production between D. sechellia and D. simulans appears to be a polygenic trait. The relationship between these factors and genes involved the adaptation of D. sechellia to its host plant is not yet clear. The data are consistent with the hypothesis that decline in egg production is, in part, a negative pleiotropic effect of genetic changes required for host specialization in D. sechellia, although finer-scale genetic analysis of both traits is needed to truly test this hypothesis.
黑腹果蝇的塞舌尔亚种是一种岛屿特有物种，专以单一寄主植物为食，其产卵率低于其泛食性的姊妹物种黑腹果蝇、拟暗果蝇和毛里求斯果蝇。早期研究表明，产卵差异的部分原因是塞舌尔果蝇相对于其姊妹物种，卵巢管数量减少。在此，我通过对塞舌尔果蝇和拟暗果蝇之间产卵差异进行遗传分析，扩展了早期的研究。在多个种间回交中总共使用了10个遗传标记，以识别影响产卵率的染色体区域。虽然之前定位的影响卵巢管数量的因素似乎会影响产卵率，但也发现了新的非卵巢管因素。总体而言，塞舌尔果蝇和拟暗果蝇之间的产卵差异似乎是一个多基因性状。这些因素与参与塞舌尔果蝇适应其寄主植物的基因之间的关系尚不清楚。这些数据与以下假设一致：产卵量下降部分是塞舌尔果蝇寄主专一化所需遗传变化的一种负面多效性效应，不过需要对这两个性状进行更精细的遗传分析才能真正验证这一假设。
