甜瓜属种间杂交线粒体DNA的遗传分析

Inheritance Analysis of Mitochondrial(mt)DNA in the Interspecific Crossing of Genus Cucumis

为探讨甜瓜属种间杂交线粒体DNA的遗传规律,对甜瓜属人工杂交合成的异源四倍体S5代新种(Cucumis hytivus Chen and Kirkbride.)及其杂交母本甜瓜属野生种(Cucumis hystrixChakr.)和父本黄瓜栽培种北京截头(Cucumis sativusL.)的线粒体中apocytochrome b(cob),NADHdehydrogenase subunit1(nad1),NADHdehydrogenase subunit7(nad7)基因序列片断进行了测序与分析,结果显示3个种长度为909 bpcob、943 bpnad1和880 bpnad7基因片断序列中分别存在着相应的1、7和17个多态性核苷酸位点,其中新种与父本北京截头相同而与母本野生种不同的多态性碱基位点分别有1、6和14个,nad1和nad7中分别只有1和3个多态性位点与双亲不相同。结果表明,甜瓜属hystrix与sativus种间杂交后代线粒体DNA的多态性碱基位点主要来源于父本而不是母本,线粒体DNA主要表现为父系遗传。

To investigate the inheritance of the mitochondrial（mt）DNA in the interspecific crossing of Genus Cucumis,fragments of the cob,nad 1,nad 7 mt gene were amplified and sequenced from S5 progenies of allotetraploid species（Cucumis hytivus Chen and Kirkbride.）,cultivated cucumber ＇BeijingJietou＇（C.sativus L.） the paternal parents and the wild Cucumis species（C.hystrix Chakr.） the maternal parents,respectively.One,seven and seventeen polymorphic loci＇s in the corresponding 909 bp cob,943 bp nad 1 and 880 bp nad 7 gene among three Cucumis species were detected,respectively.Among them,one,six and fourteen polymorphic loci＇s in the mt gene of allotetraploid were revealed to be identical as the cultivated cucumber,the paternal parents,but different from the wild species,the maternal parents;the rest one and three polymorphic loci＇s were found to be different from both parents.This result demonstrated that polymorphic loci＇s in the mt DNA of S5 allotetraploid,the hybrid progeny,were dominantly transmitted from paternal parents but not maternal parents in the hystrix×sativus interspecific crossing,and the mt DNA was dominantly paternal transmission.