A scatter plot showing the number of conserved TPAs on each human chromosome versus the chromosome size (in Mb). The chromosome X is circled. The collective size of the human genome, excluding chromosome X, is 3,098,124,053; and the size of the chromosome X after normalizing for chromosome dosage in gametes, as done by Emerson et al. , is 116,185,316 (i.e., 0.75 times the original size of 154,913,754), which harbors 13 transcribed preserved pseudogenes. Since the collective genome size is 27 times bigger than that of the human chromosome X, we expect 2 or 3 preserved pseudogenes on the chromosome X. Presence of 13 cases, an increase of more than 4.5 times than expected, suggests a statistically significant overrepresentation (exact binomial test of goodness-of-fit, P-value < 10-5, for the null hypothesis (H0) that there is no difference between the observed and expected frequencies of transcribed preserved pseudogenes on the chromosome X).
Khachane and Harrison BMC Genomics 2009 10:435 doi:10.1186/1471-2164-10-435