I'm reading this article and it says the following:

"the PRL regulatory gene HoxA-11 experienced a period of strong positive selection in the stem-lineage of eutharian mammals"

What does this mean? I'm not to sure what they mean when they're referring to stem-lineage.

3 answers

I will translate:

The PRL regulatory gene HoxA-11 experienced a period of selection during the early placenta development of mammals, such that successful reproduction was strongly favored by some variants of the gene, and others not favored for development. This positive selection for successful cell development resulted in the HoxA-11 regulation of female fertility and uterine development in mammals as we know it.
stem lineage: specialization of stem cells into specialized cells regulating growth.
Thank you so much! I really appreciate it!