Table 1.

Gene count distribution and onset of sex specificity

Sex specificity (defined at 8 wk)	Onset at 3 wk	Onset at 4 wk	Onset at 8 wk	No sex specificity	Total genes
		Number of genes
Male-specific	7	54	526*	0	587
Female-specific	9	104	512**	0	625
Sex-independent	23 (M), 56 (F)***	59 (M), 86 (F)***	0	4279	4503

The onset of sex-specificity for 1,037 out of 1,212 adult sex-specific genes occurred after 4 wk and by 8 wk. 224 of the 4,503 adult sex-independent genes met the thresholds for sex-differential expression at 3 or 4 wk, but not at 8 wk, however, only 13 of these genes showed the same sex-bias at 3 wk as at 4 wk. Three of the 7 male-specific genes showing sex specificity at 3 wk are Y-chromosome genes

* Includes 5 genes found to be male-specific at 8 wk, but female-specific at 3 or 4 wk

** Includes 6 genes found to female-specific at 8 wk, but male-specific at 3 or 4 wk

*** These genes exhibit either male-specificity (M) or female-specificity (F) at 3 or 4 wk, as noted, but show sex-independent expression at 8 wk