Dear Friends, Hi (I am not native in English, So be ready for some misunderstanding)
Most fishes lay eggs, some are live-bearing but they do not have a real placenta. in the other hand, most mammals have placenta. I like to compare an egg laying fish (e.g zebrafish), a live-bearing fish (e.g Amazon Molly) and a mammal (e.g mouse) to find the genes that are important in this evolutionary pathway.
but I do not know where to begin and to do this?
I will appreciate any suggestion.