A pedigree gone bad: increased offspring survival after using DNA-based relatedness to minimize inbreeding in a captive population

作者：Hammerly S C; de la Cerda D A; Bailey H; Johnson J A

来源：Animal Conservation, 2016, 19(3): 296-303.

DOI：10.1111/acv.12247

• inbreeding
• ex situ population
• pedigree
• microsatellite DNA
• relatedness
• mean kinship
• captive breeding

Captive breeding programs often use a pedigree to identify breeding pairs that maintain genetic diversity and limit inbreeding. However, unintentional breeding of closely related individuals can occur when errors exist in the pedigree and may subsequently result in inbreeding depression. In this study, a DNA-based approach was used to identify parentage assignment errors in the captive pedigree of the critically endangered Attwater's prairie-chicken Tympanuchus cupido attwateri, and tested whether clutch survival increased using DNA-relatedness values for assigning breeding pairs instead of the pedigree and mean kinship. Parentage assignment error was observed in each year surveyed ranging from 2.4 to 7.3%. After correcting identified errors prior to the 2013 breeding season, 11 of 38 assigned pedigree-based breeding pairs still possessed DNA-based relatedness coefficients (r(DNA)) >= 0.125 suggesting that additional errors remained in the pedigree. Two approaches were used to prevent breeding among close relatives in 2013 and 2014. Assigned pedigree-based breeding pairs in 2013 that possessed r(DNA) >= 0.125 were reassigned unrelated breeding partners, while all individuals in 2014 were used to identify the minimum overall r(DNA) for the breeding population without reference to the pedigree other than to verify founder representation. Both years resulted in a significant reduction in mean parental relatedness among chicks (P < 0.001) and a significant increase in the proportion of the clutch surviving to 5 weeks post-hatch (P <= 0.006) compared to 2012 when breeding pairs were assigned using only the pedigree. No significant difference in the proportion of the clutch surviving was observed between 2013 and 2014 (P > 0.300). These results have important implications for the captive management of endangered species, and highlight the importance of periodically evaluating for pedigree errors. To what degree pedigree errors limit fitness in other endangered species captive populations deserves further attention.

• 出版日期2016-6