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To understand the genetic diversity of buffalo Y chromosome, 14 microsatellite markers specific for cattle Y chromosomes were used to analyze 31 male buffaloes of three populations (i.e., HH, BN, and PR) originating from southeastern Yunnan Province, P. R. China. The aim of this study was to examine the practicability of cattle Y chromosome-specific microsatellite markers in studying genetic diversity of buffalo Y chromosome. Three markers (INRA008, UMN0103, and UMN0504) produced single allele, and three (UMN1113, UMN0304, and BC1.2) produced three alleles. But these markers were all monomorphic. Another three markers (UMN0920, UMN0307, and UMN3008) amplified irregular ladder-like bands. These markers were not suitable for investigating the swamp buffalo Y chromosome genetic diversity. The remaining five microsatellites (INRA124, INRA189, BM861, PBR1F1, and UMN2001) were polymorphic, which can be used to study the swamp buffalo Y chromosome genetic diversity. The mean number of alleles (Na), expected heterozygosity (He), genetic diversity (GD), polymorphism information content (PIC), and Shannon's information index (SI) across these five polymorphic loci in the buffalo population samples studied were 2.8000, 0.3998, 0.4144, 0.3245, and 0.5849, respectively, demonstrating a moderate degree of polymorphism in the Y chromosome of the buffalo population.

The main function of ZAG gene is to enable the decomposition of fat, and reduced fat content. In this study, polymorphisms of four loci (Z1, Z2, Z3, Z4) at the coding region of the bovine ZAG gene were detected in 145 Jiaxian red cattle, and polymorphisms were found on Z1, Z3, Z4 loci. The fragments showing different SSCP patterns were sequenced, nd a total of six SNPs (C115T, A3257G, A4013G, T4027C, C4032T, and T4120C) were found. The Z3 locus of ZAG gene was at Hardy-Weinberg equilibrium, while Z1 and Z4 loci of ZAG gene were not at Hardy-Weinberg disequilibrium. The association analysis of different genotypes with some of the growth and development traits showed that the individuals with genotype AC had a larger body length, heart girth, circumference of cannon bone, body weight than the individuals with genotypes AA and AB (P<0.05 or P<0.01, respectively) in Z4 locus. It is suggest that Z4 locus may be one of the marker-assisted selection used as growth traits in Jiaxian red cattle.

PCR-SSCP and DNA sequencing methods were conducted to detect single nucleotide polymorphism of alpha-lactalbumin (LALBA) gene in 452 Inner Mongolian white cashmere goats (IMWC). Correlations between SNP of goat LALBA gene and economic traits, e.g., cashmere yield, cashmere thickness, length and weight, were analyzed. The SSCP in P2 primer locus, which was caused by the point mutation M63868:g.1897T>C in the exon 3 of LALBA gene was detected. At this locus, the genotype TT and allele T were predominant in the IMWC population, which agreed with Hardy-Weinberg equilibrium. Moreover, there was a significant correlation between polymorphism of goat M63868:g.1897 locus and cashmere yield of IMWC (P=0.017). The individuals with genotype TC had more cashmere yield than those with geontype TT. Hence, genotype TC of LALBA gene can be used as a molecular marker for breeding superior cashmere yield in goat marker-assisted selection.

The aim of the present study was to identify and characterize polymorphisms within the coding region and the 3' flanking region of the bovine serotonin receptor 1B gene among different cattle breeds. Four DNA fragments were amplified by polymerase chain reaction and then used for polymorphism identification by SSCP. The fragments showing different SSCP patterns were sequenced. And a total of six SNPs (G205T, C507T, C546G, C744T, G816A and G942A) were detected. The SNPs were at Hardy-Weinberg equilibrium except C507T and C546G in all genetic population. The frequencies of allele 205T of Holstein were much higher than that of the other six beef cattle populations. Almost the PIC of all SNPs were not more than 0.10 except that of G205T in Holstein cows, which indicated the bovine HTR1B gene was conserved.

In this paper PCR-SSCP technique was used to analyze the polymorphisms of the tenth exon of GHR gene in Qinchuan cattle. The results showed that PCR products demonstrated polymorphisms in Qinchuan cattle and the population was at Hardy-Weinberg equilibrium (P > 0.05). There were three allele gene A, B, C in this locus with the corresponding frequencies of 0.5956, 0.2905 and 0.1140. The amplified fragments of homozygosis genotype were sequenced. The result showed that there were two mutation in these fragments. Then the relationship between genotypes and productive performances was analyzed by the Least Squire Method (LSM). The results showed that some productive performances of the indi-viduals with genotype AB were higher than those of the other genotypes, and the derivation was significant among geno-types. It suggested that GHR gene may be a candidate gene responsible for growth trait in Qinchuan cattle.

Random microsatellite amplify polymorphic DNA (RMAPD) is a new method of molecular marker. It can reveal genome DNA polymorphisms of organism only when random primer and microsatellite forward or reverse primer are combined together as a pair of primers by the PCR reaction system with Taq DNA polymerase, MgCl2, dNTPs and contemplate DNA. The core question of RMAPD is validity of the primers used. A lot of experiments of RMAPD in 69 Xinong Saanen dairy goats showed that RMAPD primers were effective. Comparison of RMAPD, microsatellite and RAPD markers demonstrated that RMAPD was different from each other in primers, amplification protocol and repetition. RMAPD is not equal to RAPD, but a extendable RAPD. Therefore, RMAPD is regarded as a new method of molecular marker. As it has many characteristics of DNA marker, RMAPD has a widest potential application in animal breeding and genetics, such as analysis of genetic structure and relationship and MAS.

The genetic polymorphism of Yangxian artificially reared 43 crested ibises (Nipponia nippon) was firstly investigated by RMAPD (random microsatellite amplify polymorphic DNA) marker. The results showed that RMAPD was more stable and polymorphic than RAPD. 2147 bands were amplified by 12 pairs of primers,of which 93 bands had polymorphisms. The band sharing frequency and the genetic diversity index were 0.718 and 3.664, respectively, indicating that the genetic structure of crested ibis population was simple and poor genetic variations existed in crested ibis population in Yangxian. It is imperious to protect the genetic diversity of crested ibis population.

PCR-RFLP technique was applied to analyze correlation between the polymorphisms of CSN1 S2 (alpha(s2) casein), CSN3 (kappa casein) and beta-lg (beta-lactoglobulin) genes and milk performance in 69 individuals of Xinong Saanen dairy goat. The results showed that there was significant correlation between different genotypes of CSN1 S2 locus and milk yield:average milk yield of individuals with genotype FF was less than that of genotype NN (P < 0.05); the second lactation milk yield of individuals with genotype NN was over 90 kg higher than that with genotype FF (P < 0.01). This indicates that allele F of CSN1 S2 locus probably has significant negative effect on milk yield. The results of CSN3 gene digested with endonuclease Hind III cleavage showed that no significant difference of milk yield between genotype DE and genotype EE was detected in first, second, third and fourth lactation milk yield and average milk yield (P > 0.05). The results of CSN3 gene with endonuclease Taq I cleavage showed that no significant difference of milk yield among individuals with genotype TT, TC and CC was detected (P > 0.05). No polymorphism was detected in PCR products of CSN3 gene digested with endonuclease Hae III. The analysis of beta-lg gene's 5' flanking region (710 bp) by PCR-RFLP in Xinong Saanen dairy goat showed that milk yield of individuals with genotype AA was higher than that with genotype AB in second, third lactation milk yield and average milk yield (P < 0.05). The results implied that allele A of beta-lg gene's 5' flanking region is probably related to high milk yield.

PCR-RFLP was applied to analyze the polymorphism of CSN1S2 gene in 170 goats that comprised of five goat breeds, namely Xinong Saanen dairy goat, Guanzhong dairy goat, Shaannan white goat, Angora goat and Boer goat. A 310 bp -long PCR product was digested with Alw26I and demonstrated polymorphism in five goat populations that were all at Hardy-Weinberg equilibrium (P>0.05). For Xinong Saanen dairy goat, Guanzhong dairy goat, Shaannan white goat, Angora goat and Boer goat, gene heterozygosity/effective allele gene number/Shaanon information entropy /Polymorphism information content were 0.1589/1.1889/0.2955/0.1463, 0.4114/1.6981/0.6017/0.5171, 0.1653/1.1980/0.3046/0.1516, 0646/1.0691/0.1463/ 0.0625, 0.0541/1.0572/0.1270/ 0.0526, respectively. According to the heredity diversity indexes described above of the five goat breeds, Guanzhong dairy goat had the most abundant heredity diversity and showed high polymorphism, and Xinong Saanen dairy goat and Shaannan white goat were inferior, while Angora goat and Boer goat had the lowest genetic variability.