The ratio of the number of X chromosomes to the number of autosomal sets. A diploid organism with two X chromosomes (i.e., 2X:2A) has an X:A ratio of 1:1, or 1. With one X chromosome (i.e., 1X:2A) this ratio is 1:2, or 0.50. See genic balance, sex determination.
Subjects: Genetics and Genomics.