Data from: Maintenance of genetic diversity in an introduced island population of Guanacos after seven decades and two severe demographic bottlenecks: implications for camelid conservation

Fifteen Guanacos were introduced to Staats Island in Falklands/Malvinas archipelago from Patagonia in the 1930s. After introduction, the Guanaco population increased to almost 400 animals that retained a footprint of the founding effect and bottleneck reflected in the genetic status of this isolated population. The goals of this study were to (i) make a genetic assessment of this island population through comparisons with mainland populations and simulation, and (ii) assess the likely source population of the introduced Guanacos. Genetic variation estimated from 513 bp of mitochondrial DNA sequence and 15 microsatellite loci were compared among 154 Guanacos collected from eight localities, including the adjacent mainland and the islands of Tierra del Fuego and Staats Island. Of the 23 haplotypes observed among our samples, the Staats Island population only contained three haplotypes, all of which were shared with the Monte Leon population in southern Patagonia. Mitochondrial DNA and microsatellite variation on Staats Island were comparable to most mainland populations and greater than those observed on Tierra del Fuego. Patterns of genetic structure suggest that the Staats Island Guanaco population was founded with animals from southern Patagonia (as opposed to northern Patagonia or Tierra del Fuego), but that effective reductions in population size lasted only a few generations and that surviving animals were a random sample of the pre-bottleneck genetic variation

Maintenance of genetic diversity in an introduced island population of guanacos after seven decades and two severe demographic bottlenecks: implications for camelid conservation.

Fifteen guanacos were introduced to Staats Island in the Falklands/Malvinas archipelago from Patagonia in the 1930s. Twenty five years later, the population was culled from 300 to 10-20 individuals, but quickly rebounded to a population of almost 400 animals that today retain the genetic signature of the founding event and later bottleneck. The goals of this study were to (i) make a genetic assessment of this island population through comparisons with mainland populations and simulations, and (ii) assess the likely source-population of the introduced guanacos. Genetic variation was estimated from 513 bp of mitochondrial DNA sequence and 15 microsatellite loci among 154 guanacos collected from eight localities, including the adjacent mainland and the islands of Tierra del Fuego and Staats Island. Of the 23 haplotypes observed among our samples, the Staats Island population only contained three haplotypes, all of which were shared with the coastal Monte Leon population in southern Patagonia. Mitochondrial DNA and microsatellite variations on Staats Island were comparable to most mainland populations and greater than those observed on Tierra del Fuego. Patterns of genetic structure suggest that the Staats Island guanaco population was founded with animals from southern Patagonia (as opposed to northern Patagonia or Tierra del Fuego), but that effective reductions in population size lasted only a few generations and that surviving animals were a random sample of the pre-bottleneck genetic variation

MicrosatGuanacosFalkland24-7-09b

Microsatellities dat

Genetic diversity indices from mtDNA Control Region sequences and 12 microsatellite loci by localities (defined in Table 1 and Figure 1).

<p>The right most column shows the result of Welsh’s t-test between the populations of Staats Island and each its three potential continental source populations. <i>n</i>: number of haplotypes; <i>np</i>: number of private haplotypes; <i>h</i>: haplotype diversity<i>; π</i>: nucleotide diversity; <i>A</i>: mean number of alleles per locus; <i>Ap</i>: privates alleles; <i>He</i>: mean expected heterozygosity; <i>Ho</i>: mean observed heterozygosity; <i>Welch p-value</i>: significance value of Welch's t-test between the SI population and each of the other populations (e.g. Welch t-test between SI and ML has a <i>p-value</i> of 0.2948), <i>n.p.</i>: test not performed. Deviations from zero <i>*p<0.05, **p<0.001.</i></p

Distribution of the 23 Control Region haplotypes (frequency) observed in 156 guanacos from 8 localities.

<p>The vertical numbers indicate the position of polymorphic sites relative to haplotype 1. Bold numbers emphasized the haplotypes presented in Staats Island.</p

Clustering solution of the Patagonia guanaco populations.

<p>Plot of posterior probability of assignment for 164 guanacos (vertical lines) to three genetic clusters based on Bayesian analysis of variation at 12 microsatellite loci. Individuals are grouped by locality, and localities are indicated along the horizontal axis. Genetic Cluster 1: North Patagonia group (VC, BP, SJ); Genetic Cluster 2: Tierra del Fuego group (TF); Genetic Cluster 3: South Patagonia group (ML, TP, PK, SI). Population name abbreviations follow <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091714#pone-0091714-t001" target="_blank">Table 1</a>.</p

Temporal changes in observed alleles per locus (solid line, <i>A_O</i>), and observed (solid line, <i>H_O</i>) and expected (spotted line, <i>H_E</i>) heterozygosity as predicted by a simulation of the guanaco population after introduction in Staats Island.

<p>In the simulation, year 0 represents the pre-bottleneck (source in mainland) population and the bottleneck occurred in years 1 and 22. Population size changed as indicated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091714#pone-0091714-g002" target="_blank">Figure 2</a>.</p

Summary of the <i>Lama guanicoe</i> samples used in the genetic analyses, including localities, abbreviations, geographic positions, type of sample (B = blood, F = fecal, M = muscle, S = skin, and L = liver), and total number (N) of samples used from each locality for each genetic marker.

<p>Summary of the <i>Lama guanicoe</i> samples used in the genetic analyses, including localities, abbreviations, geographic positions, type of sample (B =  blood, F =  fecal, M =  muscle, S =  skin, and L  = liver), and total number (N) of samples used from each locality for each genetic marker.</p

Pairwise population differentiations between guanaco populations.

<p>Genetic structure and statistical significance corrected by Bonferroni among Patagonia guanacos using mtDNA (pairwise <i>Ф_ST</i> over diagonal) and microsatellite (<i>F_ST</i> below diagonal) markers. Deviations from zero *<i>p</i><0.05, **<i>p</i><0.001.</p

Map of southern South America and the Falkland/Malvinas Islands with sampled localities of <i>Lama guanicoe</i> analysed.

<p>Each location indicates the relative proportion of each haplotype in yellow, blue and red relative to Staats Island. Mainland haplotypes not found on Staats Island are shown in grey scale. The size of the sphere is proportional to the number of individuals sampled.</p