翘嘴红鲌(♀)×团头鲂(♂)杂种F1的形态特征及遗传分析

Studies on morphological characteristics and genetic analysis of the hybrid F_1,Erythroculter ilishaeformis ♂×Megalobrama amblycephala ♀

2006-2007年,在浙江湖州,通过翘嘴红鲌(♀)和团头鲂(♂)间的属间杂交,成功获得了杂种F1,并通过对杂种F1及其父母本的形态、核型和基因组分析比较,探讨了杂种F1的性状变异和遗传组成情况。结果表明:(1)翘嘴红鲌(♀)和团头鲂(♂)间具有良好的亲和力,其杂交受精率、孵化率均达到90%以上;(2)翘嘴红鲌(♀)×团头鲂(♂)杂种F1的多数可数可量性状表现为中间型。在10个可数性状中,鳃耙数、侧线鳞等3个性状介于父母本之间,其平均杂种指数为54.56,显示杂种F1的可数性状接近于中间值,略偏向于父本团头鲂;在17个常规可量性状中,有9个性状与父母本差异显著,其中有4个性状偏向于父本,有3个偏向于母本,有2个超父母本偏离,其平均杂种指数为49.59,也显示杂种F1的可量性状处于中间值;进一步对框架参数的聚类和判别分析显示,杂种F1的框架体型与父母本差异较大,接近于中间型,但受母本影响较多;(3)杂种F1的染色体数(2n)为48,核型公式为18m+26sm+4st(NF=92),说明杂种F1为二倍体,并可预测杂种F1可育;(4)杂种F1大部分RAPD扩增条带能在亲本中找到,有的仅来自于父本,有的仅来自于母本,说明杂种F1为二倍体杂种;杂种F1与母本的相对遗传距离为0.4327,而与父本的遗传距离0.2312,前者大于后者,表明杂种F1与两亲本的遗传差异不是对等的,而是偏向父本一方,UPGMA系统树也同样证明了这一点。

As a result of a successful work on intergeneric crossing in fish during the years of 2006 and 2007 at Zhejiang Institute of Freshwater Fisheries, a hybrid F1 of Erythroculter ilishaeformis ♀× Megalobrama amblycephala ♂ were obtained. Further comparative analysis of morphological characteristics, karyotypes and gene groups were carried out to clarify the differences of morphological and genetic traits between the hybrid and its parents. The results are as follows, （1） both fertilizing rates and hatching rates by crossing of E. ilishaeformis ♀× M. amblycephala ♂ were above 90%, which indicates a good kin ability between female E. ilishaeformis and male M. amblycephala; （2） most numeric traits of the hybrid F1 appeared to be medium. Among ten countable traits, the numbers of gill rake and lateral scale are within the range of its parents＇, the average hybrid index is calculated to be 54.56, which interprets that the countable traits approach to the middle values and slightly incline to its male brood＇s. Of seventeen measurable traits, nine traits are significantly different from its parents＇, including four traits incliney to paternity, three to maternity and two deviating from its parents＇. The average hybrid index is calculated to be 49.59, which indicates the measurable traits are also close to the middle values. Cluster analysis and discriminant analysis of body frame indexes denote that the body shape of hybrid F1 has obvious differences from its parents, appears to be of midtype and be affected more by its maternity; （3） Chromosome numbers （2n） of the hybrid F1 are counted to be 48 and karyotype formula is described as 18 m ＋ 26 sm ＋ 4 st （NF = 92）, which is similar to those of its parents. The observations specify that the hybrid F1 is a diploid with fertility; （4） Most RAPD enlargement stripes of the hybrid F1 could be found in both parents and some are solely from either paternity or maternity, which shows a hybrid in nature. The hybrid F1 has a relative heredity distance of 0. 4327 from the maternity and 0. 2312 from its paternity. The former is farther than the later, which elucidates that the hybrid F1 has an unequal heredity difference from its parents and a genetic inclination to its paternity. This is also supported by UPGMA.