A Comparative Study On The Effectiveness Of Genetic Diversity Preservation Under Two Mating Modes In Captive Siberian Tiger

Captivity breeding is an important measure to reduce the extinction risk of the Siberian tiger (Panthera tigris altaica). In captivity, males may alternately copulate with an estrus female and result in heteropaternity in a single litter. Comparing to routine one-male-one-female mating system, multi-male mating system has potential advantages in avoiding inbreeding, improving the genetic compatibility and the genetic quality of offspring. We here carried out a study on the captive Siberian tiger population of Heilongjiang Siberian Tiger Park, and compared the effectiveness of the two mating modes in preservation of genetic diversity by using microsatellite technology. In multiple-male mating group, allelic number (A) detected on 8 microsatellite loci in offspring population ranged from 2 to 9,5.75 on average, occupying 92.00% their parents'alleles. The effective allele number (Ne) ranged from 1.9376 to 7.4926, 4.1797 on average, making up 97.61% the parents' effective alleles. The average expected heterozygosity (He) in offspring was 0.7204, about 97.56% of parents'He. In single-male mating group, allele number detected on 8 loci in offspring population ranged from 3 to 8,5.5 on average, inherited 97.73% of parents alleles, and Ne ranged from 1.5008 to 6.6759,3.7583 on average, occupying 94.99% parents'effective alleles. He for the offspring was 0.6949, making up 94.26% of parents'He. Under the two mating modes, there were no significant difference was detected for Standard individual heterozygosity (SH) between parents populations or offspring populations (P>0.05). SH of offspring was significantly lower than that of parents (P=0.029) in multiple-male mating group, but not so in single-male mating group (P=0.752). However, such difference in two mating groups became not significant (P>0.05) if relatedness of parents was considered using the effective standard individual heterozygosity (SHE). Results suggested that the two mating modes had similar effectiveness in the preservation of genetic diversity. But considering the potential advantages of multi-male mating mode over the single-male mating mode, the multiple-male mating mode highlighted a new measure of genetic management for captive populations.