共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
A. L. KROEBER 《American anthropologist》1911,13(4):577-584
10.
11.
J. Foster Palmer 《BMJ (Clinical research ed.)》1907,2(2448):1621-1622
12.
13.
Bradley M. Potts James B. Reid 《Evolution; international journal of organic evolution》1988,42(6):1245-1255
An example from the genus Eucalyptus is used to argue that hybridization may be of evolutionary significance as a means of gene dispersal where seed dispersal is limited. A previous study of regeneration of E. risdonii and E. amygdalina indicated that the current selective regime was favoring E. risaonii. However, the dispersal of E. risdonii by seeds is shown to be limited (s, = 4.6 m). By comparison, the flow of E. risdonii genes into the range of E. amygdalina by pollen dispersal and F1 hybridization is widespread (sp = 82 m). While the actual level of hybridization is low, interspecific hybridization effectively doubles the dispersal of E. risdonii genes into the range of E. amygdalina. This pollen flow can have a significant genetic impact, since isolated hybrids or patches of abnormal phenotypes have been found 200–300 m from the species boundary. Based on lignotuber size, some of these patches appear to have been founded by F1 hybrids. The frequency of E. risdonii types in the patches appears to increase with patch size suggesting that there is selection for this phenotype in subsequent generations. E. risdonii-like individuals were recovered in the progeny from both intermediate and E. risdonii backcross phenotypes. These results suggest that E. risdonii may invade suitable habitat islands within the E. amygdalina forest, independently of seed migration, by long-distance pollen migration followed by selection for the gene combinations of the pollen parent. 相似文献
14.
15.
Arthur Todd-White 《BMJ (Clinical research ed.)》1909,2(2538):499-500
16.
J. Booth-Clarkson 《BMJ (Clinical research ed.)》1909,2(2544):1010-1011
17.
18.
19.
20.