Table 1.

Reproductive fitness of the B2m deficient mouse.

Mating combination	No. of litters borna	No. of pups borna
B2m +/+ female × B2m+/+ male	43 ± 2	315 ± 10
B2m −/− female × B2m−/− male	31 ± 4*	147 ± 7***
B2m −/− female × B2m+/+ male	34 ± 6	134 ± 6***
B2m +/+ female × B2m−/− male	35 ± 7	124 ± 9***
B2m −/+ female × B2m−/+ male	39 ± 4	400 ± 19*

^aValues are presented as mean ± SEM.

^* P < 0.05 and

^*** P < 0.001 versus wild-type females analyzed by Student t-test.