摘要
杂交是自然界的普遍现象 ,并在农林业生产中发挥着重要作用 ,但如不注意亦会带来遗传危害。当把两个遗传差异较大的物种 (种群 )混植在一起时 ,我们要考虑远交衰退的危害 ,即杂交破坏了亲代具有的共适应等位基因组合 ,导致杂交后代适应性的降低 ;当杂交发生在两亲本个体 (或花粉 )数量悬殊时 ,我们就要考虑遗传同化的危害 ,即小种群一方由于产生自己“纯”后代数量的减少而被前者“稀释”掉 ,导致小种群遗传特异性丧失或灭绝。另外 ,当杂交体具有杂种优势时 ,它可取代亲本 ,威胁到亲本的生存 ;如果有害物种 (种群 )由渐渗杂交获得某种优良性状 (抗病、抗药、抗逆性等 )时 ,可能失去控制 ,造成生态危害。针对杂交在这几个方面潜在的遗传危害 ,本文在濒危物种的迁地和就地保护。
Hybridization is common in nature, and widely used to create new breeds in agriculture. However, it can cause harmful consequences. Outbreeding depression can occur when adaptive gene complexes in one species (or population) are broken down by the immigration of genes that are adapted to some other environment. This causes mal-adaptation of progeny, lowering the future species (population) fitness. Genetic assimilation may dilute the genetic diversity of a small population if it hybridizes with a larger population of a different species. That is, no genetically “pure” progeny will be produced by small populations if their parents have a high probability of hybridizing. Hybrid offspring may be fitter than either parent due to heterosis, and may spread at the expense of the parent strain, and ultimately replace it. Through introgression, species or populations may also gain some adaptive traits such as resistance to disease, adversity, or pesticides, which they have never shown before, thus making them more difficult to control. Implications and suggestions concerning in situ and ex situ conservation of endangered species, ecological restoration and so on are proposed.
出处
《生物多样性》
CAS
CSCD
2003年第4期333-339,共7页
Biodiversity Science
基金
瑞典IFS基金 (D/ 32 39 1)
中国科学院华南植物研究所所长基金
广东省自然科学基金 ( 0 0 30 31)
