capture_diversity.Gmat: Estimate Minimum Number of Individuals to Sample to Capture...

In castgen: Estimate Sample Size for Population Genomic Studies

Estimate Minimum Number of Individuals to Sample to Capture Population Genomic Diversity (Genotype Matrix)

Description

This function can be used to estimate the number of individuals to sample from a population in order to capture a desired percentage of the genomic diversity. It assumes that the samples are the columns, and the genomic markers are in rows. Missing data should be set as NA, which will then be ignored for the calculations. All samples must have the same ploidy. This function was adapted from a previously developed Python method (Sandercock et al., 2023) (https://github.com/alex-sandercock/Capturing_genomic_diversity/)

Usage

capture_diversity.Gmat(
  df,
  ploidy,
  r2_threshold = 0.9,
  iterations = 10,
  sample_list = NULL,
  parallel = FALSE,
  batch = 1,
  save.result = FALSE,
  verbose = TRUE
)

Arguments

df	Genotype matrix or data.frame with the numeric count of alternate alleles (0=homozygous reference, 1 = heterozygous, 2 = homozygous alternate)
ploidy	The ploidy of the species being analyzed
r2_threshold	The ratio of diversity to capture (default = 0.9)
iterations	The number of iterations to perform to estimate the average result (default = 10)
sample_list	The list of samples to subset from the dataset (optional)
parallel	Run the analysis in parallel (True/False) (default = FALSE)
batch	The number of samples to draw in each bootstrap sample iteration (default = 1)
save.result	Save the results to a .txt file? (default = FALSE)
verbose	Print out the results to the console (default = TRUE)

Value

A data.frame with minimum number of samples required to match or exceed the input ratio

References

A.M. Sandercock, J.W. Westbrook, Q. Zhang, & J.A. Holliday, A genome-guided strategy for climate resilience in American chestnut restoration populations, Proc. Natl. Acad. Sci. U.S.A. 121 (30) e2403505121, https://doi.org/10.1073/pnas.2403505121 (2024).

Examples

#Example with a tetraploid population
set.seed(123)
test_gmat <- matrix(sample(0:4, 100, replace = TRUE), nrow = 10)
colnames(test_gmat) <- paste0("Sample", 1:10)
rownames(test_gmat) <- paste0("Marker", 1:10)
test_gmat <- as.data.frame(test_gmat)

#Estimate the number of samples required to capture 90% of the population's genomic diversity
result <- capture_diversity.Gmat(test_gmat,
                                 ploidy = 4,
                                 r2_threshold = 0.90,
                                 iterations = 10,
                                 save.result = FALSE,
                                 parallel=FALSE,
                                 verbose=FALSE)

#View results
print(result)

castgen documentation built on April 3, 2025, 9:21 p.m.