Sex & HOX genes: learning about basic reproduction

Mosses Make Two Different Plants From the Same Genome, and a Single Gene Can Make the Difference | The Artful Amoeba, Scientific American Blog Network.

This article is pretty amazing and is VERY well-written. 

I just posted one about fish and asked why they couldn’t just asexually reproduce.  Well, this kind of starts pointing you in that direction–by looking at how living things reproduce.  For some plants, it’s not like it is for us humans.  Understanding life cycles is important to understanding where sexual reproduction comes from, and what it accomplishes.  In class, we learn that sexual reproduction provides key variation that is needed for natural selection to work on and thereby cause evolution.  This takes you through a bit of the biology of that. In particular, you get to see how moss can live as a sporophyte plant (which is diploid, like an adult human) or a gametophyte plant (also a fully, free-living plant, but it’s only haploid; it’s like our eggs and sperm BEING adult bodies on their own, which is kind of inconceivable).

Even more interesting, towards the end of the semester, we talk a little about developmental patterns in biology.  What turns genes on and off?  What makes a tadpole start going through the transformation to being a frog?  These types of developmental changes (in ontogeny) are controlled by the Hox genes.  This article actually talks about a set of genes that help control the trigger between sporophyte plant and gametophyte plant.  The way I think about it: they contribute to determining when it’s time to reproduce!

What are your thoughts?