Under-estimation of genetic diversity within wild potato (Solanum) species populations

Authors: Bamberg, John; DEL RIO, ALFONSO - UNIVERSITY OF WISCONSIN; SHANNON, LAURA - UNIVERSITY OF MINNESOTA

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/30/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Genebanks seek to know the partitioning of diversity among species, populations, and individuals in the collection, since this informs decisions for adopting the most effective approaches to collecting, maintaining and evaluating that diversity. Recent reports suggest that heterogeneity within genebank populations of primitive diploid cultivated species is much lower than tetraploids, and heterogeneity within accessions of diploid wild species is very low compared to that among accessions. This and methods used in previous genetic assays could lead one to conclude that minimum sampling (one individual) adequately represents these populations. We created several new empirical datasets and re-examined other pre-existing ones to demonstrate that unbiased estimates show high diversity within diploid populations of various potato species, especially when considering all populations of a species in the genebank, and large numbers of individuals from populations sampled directly from the wild. Sampling one plant within a population failed to detect a large proportion of the diversity in most materials by most methods. We demonstrate how diversity can be underestimated due to ascertainment bias, diploid ploidy level, sample size, and breeding systems. For example, S. jamesii, as species reported as extremely homozygous, was shown to have very high within-population heterogeneity. Minimal sampling will often fail to identify markers rare in both within and among populations—the ones that may be of most practical value for germplasm use.