SSS 2009-11-09
时间：2019-01-08 作者：英语课 分类：Scientific American(十一)月
Evolution continues today, and sometimes we can watch it happening. Researchers in the November 6th edition of the journal Science say that they caught in the act a population of butterflies in Ecuador potentially diverging 1 into two distinct species.
Heliconius butterflies spread across Central and South America. What distinguishes differing Heliconius species is color variation. For instance, in Costa Rica, the two most closely related species are white or yellow, which prefer to mate with those of their own color.
In Ecuador, there are also white or yellow Heliconius butterflies that live close to one another and have mated freely. But that situation might be changing. Scientists studied the butterflies in captivity 2. The two types differ in just one gene 3 responsible for color. But yellow males prefer yellow females. While white males go for either color female.
The difference in mate preference could eventually lead to two distinct species, as in Costa Rica, with yellow and white butterflies that no longer interbreed. The researchers will continue to study the role of genes 4 in both color and mate choice—which could send the populations diverging forever into new species.
- Plants had gradually evolved along diverging and converging pathways. 植物是沿着趋异和趋同两种途径逐渐演化的。
- With member-country bond yields now diverging, 'it's a fragmented set of markets. 但随着成员国债券收益率之差扩大，市场已经分割开来。
- A zoo is a place where live animals are kept in captivity for the public to see.动物园是圈养动物以供公众观看的场所。
- He was held in captivity for three years.他被囚禁叁年。
- A single gene may have many effects.单一基因可能具有很多种效应。
- The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。