Six of the 11 mice from which the progeny had been examined after the first delivery had infected at least 1 of their pups.
Among the 7 pups born, 5 were black and 2 were grey.
Only rats that bred at least six pups were used.
Recipient females were allowed to deliver and raise their own pups.
Furthermore, cross-fostering studies demonstrate the importance of maternal behavior as a regulator of the development of regulatory systems in their pups.
Ten pups from five litters born during 1998 were monitored from weaning to approximately 12 weeks of age for nematode infections.
The female pronucleus to some extent also has effects on progeny hair colour, which is proved by the production of 2 pups with grey hair.
The scalp was then sutured, the pup warmed and returned to the dam.
