RAPD and microsatellite analysis of autotetraploid,diploid and reciprocal interploid triploids of blunt snout bream,Megalobrama amblycephala
【摘要】：正RAPD and microsatellite markers were used to investigate levels of genetic variation within autotetraploid (auto-4n), diploid (2n) and reciprocal inter-ploid triploids (3n- and 3n+) of blunt snout bream. The specific 390-bp and 510-bp fragment amplified by S137 primer was present in 2n and auto-4n population, respectively, and both 390 bp and 510 bp fragments were present in 3n-and 3n+ population. The mean percentages of polymorphic loci by RAPD were 21. 76% , 20. 23% in 3n-and 3n+ , respectively, similar to that (21. 02% ) of the 2n group, but significantly (P 0. 05) higher than 13. 85% in auto-4n. The average genetic diversity indices estimated by using Shannon's index of phenotypic diversity by RAPD were 0. 322, 0. 314 in 3n- and 3n+, respectively; significantly (P 0. 05) higher than 0. 205 in auto-4n. The mean numbers of genotypes per microsatellite locus were 4. 25, 4. 00 in 3n- , 3n+, respectively, higher than 3. 5, 3. 5 in auto-4n and 2n, respectively. Relative high ratio of tri-allelic heterozygote by microsatellite analysis was found in both populations of 3n- and 3n+. Dendrogram generated from the genetic distance of RAPD and microsatellite was similar. The topology showed two monophylies. One consisted of the autotetraploid and 2n populations. The other was composed of 3n+ and 3n- populations.