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1/n - 
Coolness alert Two fantastic stories on #spermatogenesis out today, each one a labor of love by my dear colleagues @AntoineMolaro and @SniaGPereira1. Let's dive right in... 
Coolness alert Two fantastic stories on #spermatogenesis out today, each one a labor of love by my dear colleagues @AntoineMolaro and @SniaGPereira1. Let's dive right in...
2/n - @AntoineMolaro observed something quite striking: a mouse testis-expressed histone variant (H2A.B) that is largely dispensable for spermatogenesis but has an effect on post-fertilization development (by impacting embryo viability and growth). https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001001#pbio-3001001-g001
3/n- This peculiar type of paternal epigenetic inheritance seems to be due to broad alterations in the chromatin of post-meiotic germ cells. Such alterations do not significantly impair spermatogenesis, but render paternal chromatin slightly less effective to sustain embryo dev.
4/n- This neat concept mirrors what we have previously observed for another chromatin regulator (MLL3/4), but from a female perspective. Insect oocytes lacking this regulator are morphologically normal, but incapable of initiating post-fertilization dev. https://www.embopress.org/doi/full/10.15252/embr.201845728
5/n- Collectively, both studies highlight the concept that gametogenesis and embryogenesis can respond differently to the same epigenetic insult. Perhaps in the near future we will hear about unexpected conflicts between these two intertwined biological processes.
6/n- For more on this story, check out the great thread by co-author @HarmitMalik 
https://twitter.com/HarmitMalik/status/1341820152401162240?s=20
https://twitter.com/HarmitMalik/status/1341820152401162240?s=20
7/n- The second story comes from my @IGCiencia sistah @SniaGPereira1. She studied how centrioles are assembled during plant spermatogenesis and noticed a most unusual effect… https://www.biorxiv.org/content/10.1101/2020.12.21.423647v1
8/n- Sónia observed that although both centrioles are born identical, they mature asymmetrically, with one having a shorter “scaffold”. Since the sperm cells in this plant species are biflagellated, this asymmetry may avoid that the beating of the two tails cancels each other out
9/n- Indeed, Sónia saw that, most of the time, sperm cells only have one of the two flagella actively beating. This suggests that the centriolar asymmetry may be a trick employed by this plant’s sperm to ensure progressive motility (by making one flagella slightly less efficient)
10/n- This finds some parallel with human sperm cells, which also contain two “asymmetric” centrioles: one involved in flagellar movement, the other in the formation of the neck region of the sperm (and in post-fertilization development). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6781795/
11/11- To wrap up, both studies not only report super-cool findings but are perfect examples of the importance of an evolutionarily-oriented thinking in germ cell biology. Let's see what 2021 has in store in this regard... Peaceout!
