We used Geodia spp. as models because they are gonochoristic, so that means females and males will have a set of specific genes and we didn't have the complication of setting those apart in hermaphrodites. And sequenced the hell (transcriptomes) out of them (2/n)
First thing we noticed is that males and females use slightly different germ cell pathways to trigger their cells to become gametes, with usual suspects nanos, pumilio and piwi having more of a role in ♂️ (3/n)
Another super interesting result was the involvement of the retinoic acid pathway in the actual trigger of gametogenesis, in both males and females, but more prevalently in ♂️ (4/n)
And then the usual steps in every gametogenic process, cell growth and differentiation, vitellogenesis and reorganization of the extracellular matrix for ♀️, and more clearly meiotic machineries and axoneme assembly for ♂️ (5/n)
But sponge oocytes are more interesting than other oocytes, because sometimes they come with some friends...yes, bacteria! They help them settle the symbiotic relationship right after metamorphosing...and give them advantages for the deep-sea life! (6/n)
And sponge sperm is no different than any other kind of sperm, they need capacitation (to make things quicker!) and sponges use the same pathways you would expect operating in many other animals you would consider (ehem) more complex (7/n)
Here is a summary of all that happens in these process...(8/n)
But why is all this important to you? 1⃣ Because sponges are incredibly awesome and complex, even when you see them doing "nothing" in the water, just being beautiful...(9/n)
2⃣Because they come up with the solution to make gametes that we still use...more than 600 million years ago!! Way before the dinosaurs roamed the Earth...(10/n)
and 3⃣Because they do this without all the stuff we put in our gonads (accessory cells, envelopes, coating, etc)...because sometimes the simplest solution is so elegant that still prevails over millions of years (11/11)
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