Genetic Distance and Heterozygosity Estimates in Electrophoretic Studies: Effects of Sample Size

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Abstract
An empirical analysis of the effects of sample size on genetic distance estimates [D] (Nei, 1972) and on heterozygosity estimates in electrophoretic studies is presented. Genetic distance estimates are hardly affected by sample size. A single individual may be used to represent a species for interspecific comparisons. The genetic distance estimates with sample size of 1 deviate from large sample size estimates by a Nei distance (D) .ltoreq. 0.1 in well over 90% of all pairwise comparisons. The estimated D with sample size of 1 shows systematic error, usually overestimating the full population D estimate. The error in D estimates with sample size of 1 may increase with increasing heterozygosity of the populations but remains small enough that it hardly influences phylogenetic inferences. A sample of 8-12 individuals'' yields, on the average, a heterozygosity estimate within 1% of the percent of heterozygosity calculated for larger samples. A sample of only 2 individuals will usually yield a heterozygosity estimate within 2.5% of the percent of heterozygosity calculated for a much larger sample. Heterozygosity estimates and genetic distance estimates are far more severely affected by the number of loci sampled than by the number of individuals sampled. [Anolis lizards are examined.].