| The genetic diversity as well as the genetic distances existing between common chicken populations in Jinghai Company, Haimen-China were estimated by two-fold techniques called random amplified polymorphic DNA (RAPD) assay and microsatellite markers analysis. The potentials of RAPD and microsatellites as precise tools to measure heterozygosity (gene diversity) in populations and other basic population genetic data were demonstrated. In the two assay techniques, a total of seventy-five genetic markers were employed in the preliminary analysis. For the RAPD assay alone, sixty short arbitrary primers including (S241-S260, S1081-S1100 and S1341-S1360), were employed in the polymerase chain reaction (PCR) to amplify DNA in individual genomic DNAs representing 4-major chicken populations in Jinghai Company, Haimen, Jiangsu Province, China, called Rugao yellow chicken (RYC), Jiangchun yellow chicken (JYC), Wan-Nan yellow chicken (WYC) and Cshiqishi yellow chicken (CYC), respectively.From a total of 240 isolated genomic DNAs comprising RYC (60), JYC (60), WYC (60) and CYC (60), ten genomic DNA samples were randomly selected from each of the four chicken populations. The randomly selected samples were all used as initial template DNAs and were amplified with all the 3-score 10-mer random primers. Five (5) of the random primers (S246, S249, S1083, S1088 and S1092), representing 8.3333% of the total random primers tested that generated obvious polymorphic patterns, interpretable and reproducible bands were selected as criterion primers and used in subsequent analyses. The selected random primers were used for the amplification of both theindividual DNA samples in each population and for bulked (pooled) samples of each population, respectively.The results showed that the five selected primers produced a total of 160 stable and characteristic band patterns with molecular size ranging from 835 base pair (bp) in Rugao chicken produced by primer S246 to 5033 bp in Jiangchun chicken produced by primer SI092. The average number of DNA bands produced per population by all the criterion primers was 40, with an average of 8 bands per primer in each population. The proportion of polymorphic bands across all populations was 130 (81.2500%) and 30 (18.7500%) were monomorphic in all the populations using the five criterion random markers. With the same selected primers and with the pooled population DNA samples, 53 fragment bands were also generated with size ranged from 840 (primers SI083 and SI088) to 4983 bp (primer S246): of which 27 (50.9433%) were also polymorphic. Each marker produced between 6 (primer SI092) to 13 (primers S246 and SI083) bands. The proportions of shared fragments (band-sharing coefficients-BSC) of individuals within population as well as among populations of bulked samples were calculated. The mean BSC within population ranged from 0.8928 + 0.02 (Rugao) to 0.9497 + 0.01 (Jiangchun). Of the pairwise populations, the mean BSC ranged from 0.6778 + 0.06 (Rugao vs. Wan-Nan) to 0.9313 + 0.03 (Jiangchun vs. Cshiqishi). The average percent difference (APD%) within population was between 5.0300 + 0.67 to 10.7220 + 2.40, and APD of pairwise populations ranged from 6.8700 + 3.31 to 32.2180+5.87. Heterozygosities (H) were 0.3664, 0.4217, 0.4825 and 0.4933 for Jiangchun, Cshiqishi, Wan-Nan and Rugao chicken populations, respectively. For various combinations of populations, 'H' was between 0.4153 (Jiangchun vs. Cshiqishi) and 0.7242 (Rugao vs. Wan-Nan). The cumulative power of discrimination (CPD) with the RAPD technique was 90.3921%. The Nei's standard genetic distance (D_ij) of the RAPD assay was between 0.0083 (Jiangchun vs. Cshiqishi) to 0.2789 (Rugao vs. Wan-Nan) in all the populations examined.The same sets of individual DNAs from the four chicken populations were also used to examine the genetic variability with 15 pairs of 'second-generation markers' (microsatellites). Based on the microsatellite loci and data generated from the experiment, the total numbers of alleles were 116 in the 4-chicken populations...
|
PDF Full Text Request