Several genes that contribute to human height appear to be located in the terminal region of the p arm of the X chromosome.


(a) Discuss why these regions on the tips of the X chromosome are considered to be pseudo-­autosomal.

(b) Discuss whether these genes are inactivated on the X chromosome that undergoes X inactivation.

(c) Explain why people with the karotype 45,X are usually much shorter than average.

(d) Explain why people with the karyotype 47,XXY or 47,XYY are usually much taller than average.