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Relatedness value

Figure 10.6. Estimated relatedness (R) values among giant pandas of known relatedness at the China Conservation and Research Centre for the Giant Panda and the Chengdu Research Base of Giant Panda Breeding. All wild-caught animals were assumed to be unrelated for this calculation but the complex nature of the curves indicated that this assumption was probably not true. Some animals appeared to be related to the degree expected, whereas others appeared more related than expected. Relatedness among animals can be estimated based on the microsatellite data, and this information could be useful in planning pairings for future matings.

resources that can be used to identify individuals in field studies, to assess parentage and to monitor genetic diversity. Even when cubs are born as a result of AI with semen from a single sire, it would be prudent to confirm the identity of the sire by microsatellite analysis to rule out AI errors (e.g. the mislabelling of vials of frozen semen). Finally, the establishment of genome banks to preserve samples from all captive-born and wild-caught animals could prove to be an invaluable resource for future genetic studies (Wildt, 2000; Ryder et al., 2001), including perhaps assisting with the more accurate censusing of the wild population.

Faecal and hair samples from giant pandas have proven to be good sources of DNA for microsatellite analysis (authors' personal observations). While sightings in the wild are rare, field scientists often encounter giant panda faeces and hair. It has been proposed that microsatellite analysis on DNA isolated from such sources could be used to estimate population size more accurately and determine home ranges as well as the ranges of overlap among animals (M. Durnin, pers. comm.). Based on findings presented in this chapter, the authors support this concept and also suggest that results could be used to estimate genetic relatedness within populations. Faecal samples have the added benefit of (so far) being exempt from CITES regulations and, thus, easier to share across national boundaries.

In summary, today more than 160 giant pandas reside in Chinese and western zoological institutions. Natural and assisted mating of giant pandas has led to the birth of more than 200 cubs in China in the past three decades. However, many of these offspring were born after both natural mating and AI, making the paternity of cubs uncertain. A modern 'state-of-the-art' molecular genotyping centre was established in the Laboratory of Genetics and Reproductive Studies at the Chengdu Research Base of Giant Panda Breeding. A parentage assessment involved determining the composite microsatellite molecular genotype (n = 17 loci) of 71 giant panda DNA samples. Unequivocal paternity and maternity were established for 48 of 50 cubs. In cases where both natural mating and AI were performed, all offspring were derived from the natural mating sire. This largely reflects the delay in AI procedures until after the oestrual peak. Fifteen twin births were determined to be exclusively dizygotic and, in only one case, from more than a single sire. An analysis of microsatellite genotype related-ness suggests that some founders from both centres may share previously undisclosed consanguinity. The full genotype data set is publicly available on http://home.ncifcrf.gov/ccr/lgd and should be useful in managing mating to preserve genomic diversity among captive giant pandas.

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