Data from: Genetic pedigree analysis of the pilot breeding program for the rediscovered Galapagos giant tortoise from Floreana island

An aim of many captive breeding programs is to increase population sizes
for reintroduction and establishment of self-sustaining wild populations.
Genetic analyses play a critical role in these programs: monitoring
genetic variation, identifying the origin of individuals, and assigning
parentage to track family sizes. Here we use genetic pedigree analyses to
examine three seasons of a pilot breeding program for the Floreana island
Galapagos giant tortoise, C. niger, that had been declared extinct for
~150 years until individuals with mixed ancestry were recently discovered.
We determined that eight of nine founding individuals were assigned
parentage to at least one of 130 offspring produced, though there was
considerable reproductive skew. In addition, we observed that genetic
diversity of the progeny was lower than that of the founders. Despite the
observed reproductive skew, we did not see evidence for assortative mating
based on relatedness, but there was a trend towards reduced fitness when
more related individuals bred. Finally, we found that the majority of
progeny had ancestry assigned to the Floreana species (mean±SE =
0.51±0.02), though individual estimates varied. The success of these pilot
seasons bodes well for a larger breeding program to help restore the
previously extinct tortoise from Floreana island. Future efforts should
continue to monitor for reproductive skew and assortative mating in order
to maintain allelic diversity. We would also recommend forming smaller
breeding groups and rotating individuals among them to prevent long-term
reproductive skew among pairs.