diff --git a/R/snps-data.R b/R/snps-data.R
index 7b30122f1ebeb29e2b3b7e1cb0ccbd80a22e45d9..f2817835d31355fb393667f53366242e1e987a15 100644
--- a/R/snps-data.R
+++ b/R/snps-data.R
@@ -5,8 +5,8 @@
 #'
 #' @format A data frame with 20 rows and 12 variables:
 #' \describe{
-#'   \item{positions}{location of the SNP on the chromosome}
-#'   \item{distances}{genetic distance of the SNP from the start of the chromosome}
+#'   \item{positions}{location of the SNP on the chromosome e.g. in base pairs}
+#'   \item{distances}{genetic distance of the SNP from the start of the chromosome e.g. in centimorgans}
 #'   \item{chrom_1}{allele of the SNP on the first example chromosome}
 #'   \item{chrom_2}{allele of the SNP on the second example chromosome}
 #'   \item{chrom_3}{allele of the SNP on the third example chromosome}