10.5061/DRYAD.7TP3SG0
Jensen, Evelyn L.
University of British Columbia
Edwards, Danielle L.
University of British Columbia
Garrick, Ryan C.
University of Mississippi
Miller, Joshua M.
Yale University
Gibbs, James P.
Queens College, CUNY
State University of New York
Cayot, Linda J.
Galapagos Conservancy; Fairfax Virginia
Tapia, Washington
National Park Service
Caccone, Aldalgisa
University of British Columbia
Russello, Michael A.
University of British Columbia
Caccone, Adalgisa
Yale University
Data from: Population genomics through time provides insights into the
consequences of decline and rapid demographic recovery through
head-starting in a Galapagos giant tortoise
Dryad
dataset
2018
Captive Populations
Chelonoidis duncanensis
Wildlife Management
2018-07-19T14:10:39Z
2018-07-19T14:10:39Z
en
https://doi.org/10.1111/eva.12682
30154450 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Population genetic theory related to the consequences of rapid population
decline is well-developed, but there are very few empirical studies where
sampling was conducted before and after a known bottleneck event. Such
knowledge is of particular importance for species restoration, given links
between genetic diversity and the probability of long-term persistence. To
directly evaluate the relationship between current genetic diversity and
past demographic events, we collected genome-wide single nucleotide
polymorphism data from pre-bottleneck historical (c.1906) and
post-bottleneck contemporary (c.2014) samples of Pinzón giant tortoises
(Chelonoidis duncanensis; n=25 and 149 individuals, respectively) endemic
to a single island in the Galapagos. Pinzón giant tortoises had a
historically large population size that was reduced to just 150-200
individuals in the mid 20th century. Since then, Pinzón’s tortoise
population has recovered through an ex situ head-start program in which
eggs or pre-emergent individuals were collected from natural nests on the
island, reared ex situ in captivity until they were 4-5 years old, and
subsequently repatriated. We found that the extent and distribution of
genetic variation in the historical and contemporary samples was very
similar, with the latter group not exhibiting the characteristic genetic
patterns of recent population decline. No population structure was
detected either spatially or temporally. We estimated an effective
population size (Ne) of 58 (95% CI = 50-69) for the post-bottleneck
population; no pre-bottleneck Ne point estimate was attainable (95% CI =
39-infinity) likely due to the sample size being lower than the true Ne.
Overall, the historical sample provided a valuable benchmark for
evaluating the head-start captive breeding program, revealing high
retention of genetic variation and no skew in representation despite the
documented bottleneck event. Moreover, this work demonstrates the
effectiveness of head-starting in rescuing the Pinzón giant tortoise from
almost certain extinction.
SNP genotypic data for the contemporary sample of Pinzón Galapagos giant
tortoises (Chelonoidis duncanensis)vcf file containing SNP genotypic data
at 7,730 loci for the contemporary population sample (n = 149) of the
Galapagos giant tortoises endemic to Pinzón Island (Chelonoidis
duncanensis)Jensen_contemporary_7730loci.vcfSNP genotypic data for the
contemporary and historical samples of Pinzón Galapagos giant tortoises
(Chelonoidis duncanensis)vcf file containing SNP genotypic data at 2,218
loci for the historical (n = 25) and contemporary (n = 149) population
samples of the Galapagos giant tortoises endemic to Pinzón Island
(Chelonoidis duncanensis)Jensen_historical_contemporary_2218loci.vcf
Galapagos
Ecuador
Pinzón Island