The analysis in this study implies that transcriptional changes during early involution may function, in part, to revert the mammary gland to the pre-lactation state.
In other words, 68% of the transcriptional changes between L9 and I2 can be attributed to a partial return to the pre-lactation state.
However, the observed partial convergence of the early involution transcriptional state towards the pre-lactation state is not suggested by their visualization.
This graph hints at the possibility of a convergence to the pre-lactation state at the time of early involution, but it does not directly test the number of genes different between the late pregnancy time points and involution.
In this study, for the particular question of whether the early involution transcriptional state is a partial reconvergence to the pre-lactation state, the pairwise differences are directly measured so the observed distances are unequivocal.
First, the state space of the transcriptome gradually diverges from the onset of pregnancy through lactation and then, at involution, the transcriptome partially converges to the pre-lactation state.
Second, GO analysis demonstrated that functionally, the transcriptional state is largely a reversion to the pre-lactation state – 85% of the enriched GO terms associated with up-regulation during involution exactly match GO terms of the genes down-regulated during lactation.
During pregnancy, Csf1 op / op glands develop precocious alveolar units but fail to switch to the lactational state resulting in impaired lactation [ 5].
To exclude the possibility that Dock1 and Rac1 are required for the progression to the lactating state, we stained Lac10 (10 days of lactation) glands of both genotypes for the lactation marker pStat5.
The buffalo diet seems tohave a major role in colostrum composition [10], but also the lactation, age, season, state of health, breed and geneticinput of the parents [11 14].
