Study On DNA Molecular Marker Of Growth Development Traits In Qinchuan Cattle And Its Hybrid Offspring Cattle

Four cattle populations, including purebred Qinchuan cattle(Q) and hybrid offspring cattle, Limousin cattle×Qinchuan (LQ), Red Angus×Qinchuan (AQ), German Yellow cattle×Qinchuan(DQ), aged 4 months,totally 164 beef cattle, were used as research populations. The DNA molecular marker technology, such as PCR-RFLP, PCR-SSCP, microsatellite marker, were applied to evaluate the effects of genotypes on 10 microsatellite loci and four candidate genes: POU1F1 gene, GH gene, LEPTIN gene, IGFBP3 gene, and also to detect genetic diversity in four populations. The performance traits, including the body weight, body length, heart girth, withers height, height at hip cross, hip width, rump length and ischium width, were associated between genetic marker and performance traits using general linear model(GLM). The results were as follows, 1 Research on PCR-RFLP in Q,LQ,AQ and DQ populations The polymorphic PCR-RFLP locus on the POU1F1 gene was examined in four populations. In Q, DQ, LQ and AQ populations, the heterozygosity /effective allele gene number/polymorphism information content were listed for 0.3556/0.2934/0.2963/0.4444,1.5519/1.4152/1.4210/1.7998,and 0.2924/0.2503 0.2524/0.3456, respectively. The polymorphisms of POU1F1 were associated with the bovine growth traits, which showed that in heart girth, height at hip cross, individuals with genotype AB and BB in populations were higher than that of genotype AA, namely, BB,AB>AA(P<0.05). 2 Relationship of microsatellite markers and growth traits in Q,LQ,AQ and DQ populations The genetic polymorphisms of four populations were detected using 10 microsatellite DNA markers. The polymorphism information contents(PIC) were all above 0.5, belonging to highly polymorphic loci. Among all the loci, observed allelic number(Na),the effective allelic number(Ne) and PIC of ETH152,ETH225,HEL9 were higher correspondingly; the Na, Ne, PIC of BM1500,TGLA126 were lower correspondingly. The Chi-Square test for goodness of fit showed Hardy-Weinberg disequilibrium was statistically significantly over all the selected loci in four populations (P<0.01). The effects of genotypes of 10 microsatellite loci on growth traits were diverse. The results showed that genotype CH of ETH225 was lower than other genotypes (P<0.05) as for withers height, height at hip cross and rump length. The genotype BC of BM1500 was higher than genotype BD on height at hip cross, heart girth and body weight. At HEL5 locus, BD and EH were higher than others. The genotype CG of BM2113 was higher than CF,BF as for withers height, body length, hip width, heart girth and body weight. The genotype BG of CSSM66 was higher than genotype AE on withers height, height at hip cross and heart girth. The genotype BG of HEL9 was higher than genotype EJ as for withers height, height at hip cross, heart girth, rump length and body weight. 3 The polymorphisms of PCR-SSCP of GH,LEPTIN,IGFBP3 and the relationship with growth and development traits ⑴The polymorphic PCR-SSCP locus in the GH exon5 was examined in the 4 populations and was associated to the bovine growth traits. The result showed that withers height, body length, heart girth and body weight with genotype AA, AB were higher than those of beef cattle with genotype BB(P<0.05). ⑵The polymorphisms of GH exon5 were associated to the bovine growth traits. The result showed that withers height, height at hip cross, heart girth, rump length, body weight with genotype BB, AB were higher than those of beef cattle with genotype AA(P<0.05). ⑶The polymorphisms of Leptin exon2 were associated to the bovine growth traits. The result showed that heart girth and body weight with genotype AB were higher than those of beef cattle with genotype BB(P<0.05). ⑷The result at IGFBP3 exon2 using PCR-SSCP showed that the difference between genotypes AA, AB and BB(P>0.05)in four populations were inhomogeneous. 4 Research on heterosis and growth characteristic traits in 3 crossbreds of LQ,DQ,AQ and a purebred Qinchuan cattle(Q). This paper researched the heterosis and growth characteristic traits in the four populations. The result showed that the hybrids, compared with the purebred Qinchuan Cattle, had significant heterosis on the traits of body weight, body length, heart girth, withers height, height at hip cross. The conclusion is that the hybrids were better than Qinchuan Cattle on growth characteristic traits. Among these populations, LQ was best population on these traits. All those proved that hybrid of Qinchuan with Limousin Cattle, namely LQ, had obvious hybridism predominance, and was a good crossbreeding. Meanwhile, AQ and Q had superiority on post-breeding and color of fur.