Detection of multiple paternity in green turtle clutches during a reproductive season at Khram Island, Thaiand

Abstract

Although direct observations have been suggesting that multiple mating in green turtle (Chelonia mydas) may be quite common at Khram Island, Chonburi, Thailand, the number of successful males is still in question. Genetic analysis technique is a tool for investigation. We preliminary evaluated the proportions of successful breeding males and females of green turtle in a natural population at Khram Island, Gulf of Thailand, using two microsatellite markers. We analyzed genotypes of 77 tissue samples collected from 3 nesting females, and at least seven offsprings per clutch in three successive clutches within a reproductive season (total of nine clutches). We were able to detect multiple paternity of the hatchlings. For most clutches, at least two males successfully sired hatchlings within each clutch. Throughout a nesting season, at least three different males could mate with the same female and there were at least seven males successfully mating with this set of females. This study confirmed the effectiveness of microsatellite DNA markers in detecting multiple paternity within natural populations of green turtle. However, to reduce the confounding effects of mutations on allele assignment and to increase power to monitor individual's genetic contribution, we need additional variable genetic markers.