A piece on human tails and how we lost them caught my eye so I’ll start my weekly reads with that. This week I had the fewest Zoom meetings in ages, which allowed me to get more work done in my own lab and more reading. How about that? I even had some in-person meetings too. Some day maybe such feelings of a normal life in science will be the norm again and not the exception.
Human tails
How Humans Lost Their Tails, Carl Zimmer, NYT. This is a fun article and I highly recommend it.
In a sense we didn’t lose our tails completely because we still have them for a time when we are a fetus. At some point the tail cells (except what is left as the coccyx) must apoptose?
I actually read up on this in the last few years for the book my daughter Julie and I wrote about how to build a dragon. One idea was to play around with the features of the dragon’s tail.
Zimmer’s piece is based on a new preprint: The genetic basis of tail-loss evolution in humans and apes. This preprint focused on alterations in TBXT (Brachyury or T) as a proposed basis for how we lost our tails.
Many genes are important in tail development and probably in the loss of tails in adult humans. When I was a postdoc, some of the Myc/MycN knockout mice that I produced had unusual tails. These included short or kinked tails.
Note that in extremely rare cases humans can be born with tails.
More reading: papers and media
- Reversible reprogramming of cardiomyocytes to a fetal state drives heart regeneration in mice, Science. We’ve seen other in vivo reprogramming studies in mice. It just seems too risky to really ever apply to humans clinically or even test the idea in a person. More OSKM eventually leads to tumors in the study.
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Picking Embryos With Best Health Odds Sparks New DNA Debate, Bloomberg. The first babies born with genetic selection?
Pericyte-derived fibrotic scarring is conserved across diverse central nervous system lesions, Nature Communications
Human microglia states are conserved across experimental models and regulate neural stem cell responses in chimeric organoids, Cell Stem Cell
Reconstructing aspects of human embryogenesis with pluripotent stem cells, Nat Comm. From a team led by Magdalena Zernicka-Goetz. I’ve written several times about human embryo modeling using stem cells. Now that ISSCR has backed away from the 14-day rule on human embryo growth we also should be asking (and I have) how long model human embryos can be grown. Also, as these models get more similar to the real thing, ultimately how will we tell them apart?