Dosage compensation is less effective in birds than in mammals

Journal of Biology

Table 1 Male:female ratios of expression for A and X or Z genes in four species

Species and tissue	A mean	A median	X or Z mean	X or Z median	Male X:A or Z:A ratio	Female X:A or Z:A ratio
Mouse
Brain	1.00	1.00	0.997	0.997	1.30	1.28
Muscle	1.01	0.990	0.967	0.960	0.866	0.875
Liver	1.03	0.993	1.01	0.975	0.726	0.729
Adipose	1.02	0.976	1.04	0.989	0.768	0.755
Human
Hypothalamus	1.03	1.01	1.01	1.000	1.03	1.05
Muscle	1.02	1.01	0.990	0.989	1.14	1.26
LB cells	1.00	1.00	0.973	0.987	N/A	N/A
PBM cells	1.00	1.00	1.00	1.001	0.979	0.981
Zebra finch
Adult brain	1.04	0.988	1.29	1.25	N/A	N/A
P1 brain	0.994	0.957	1.23	1.16	N/A	N/A
Liver	0.984	0.950	1.19	1.07	N/A	N/A
Kidney	1.04	1.01	1.13	1.09	N/A	N/A
Chicken
Brain	0.997	1	1.40	1.34	1.03	0.771
Heart	1.02	1.02	1.34	1.31	0.923	0.707
Liver	0.989	0.978	1.24	1.20	1.08	0.877