Individual identification and parentage analysis of Struthio camelus (ostrich) using microsatellite markers.

Abstract

Ostrich (Struthio camelus) breeding is a well-developed industry in South Africa. However, successful genetic management has yet to be implemented. Parentage in colony breeding ostriches is unknown, where for a given offspring, a number of possible parents exist. Molecular markers have been extensively used in the livestock industry to resolve parentage issues and are only beginning to be utilized to address the issues of the ostrich industry. The aims of this investigation were to test known microsatellite markers developed for other ostrich subspecies in a South African Black ostrich population, and to further test these markers for their use in individual and parentage identification. DNA was extracted from venous blood obtained from two pair bred families and a colony of 97 individuals. Eleven polymorphic microsatellite markers were tested by PCR amplification of DNA samples followed by multiplexing on polyacrylamide gels to generate DNA fingerprints for each individual. Alleles were sized and quantified and used to create genotypes for each individual. Parentage analysis was performed using exclusion and likelihood methods. Pedigrees were constructed for the families by comparison of genotypes. Breeding statistics were calculated for the colony individuals. Three microsatellite markers did not amplify in this population and one marker was found to be monomorphic in this population. Four of the microsatellite markers that successfully amplified produced anonymous amplification products suggesting a second annealing site in the genome sequence of Blacks. All loci displayed low observed heterozygosities indicative of little genetic variation in this population. For the colony sample, four individuals were not assigned either parent and one female did not contribute any offspring. On average females produced 4.86 ± 2.71 fertile eggs during the sampling period with a coefficient of variation of 55.86%. A total of 79.2% of individuals were assigned paternity and 88.3% were assigned maternity. A greater number of loci are required to improve the power of parentage analysis within breeding flocks incorporating all eggs laid.