Magic embryology: controlled aging (Introduction)

by David Turell , Thursday, November 10, 2022, 17:47 (745 days ago) @ David Turell

A new study in fetuses:

https://www.sciencenews.org/article/embryos-biological-clock-development

"As people age, so do all of our cells, which accumulate damage over time. But why our offspring don’t inherit those changes — effectively aging a child even before birth — has been a mystery. “When you are born, you don’t inherit your parents’ age,” says Yukiko Yamashita, a developmental biologist at MIT who studies the immortality of germline cells such as eggs or sperm. “For some reason, you are at zero.”

"Experts once thought that germline cells might be ageless — somehow protected from the passage of time (SN: 3/10/04). But studies have shown signs of aging in eggs and sperm, dispelling that idea. So researchers have hypothesized that germline cells might instead reset their age after conception, reversing any damage.

"In a new study, scientists describe evidence that supports that rejuvenation hypothesis. Both mouse and human germline cells appear to reset their biological age in the early stages of an embryo’s development. A rejuvenation period that takes place after an embryo has attached to the uterus sets the growing embryo at its youngest biological age, dubbed “ground zero,” researchers report June 25 in Science Advances.

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"The scientists were studying the embryos’ biological ages, which refers to the function and health of cells, in contrast with chronological ages, which mark time in years (SN: 7/13/16). By tracking epigenetic changes, the team found that the age of the mouse embryos stayed constant during the first stages of cell division immediately following fertilization. But by around 6.5 to 7.5 days into development, after an embryo attached to the uterus, the average biological age of embryos had dipped — a sign that cells were undergoing some type of rejuvenation event. A mouse embryo’s ground zero may be somewhere between 4.5 to 10.5 days after fertilization, the researchers say. At some point during development, though the exact point is still unclear, mouse embryos’ biological age then began to climb.

"Studying human embryos at the earliest stages of development is prohibited, so similar data for humans was unavailable, Gladyshev says. But some human embryos that were slightly farther along in development than the mouse embryos didn’t immediately age, a hint that a similar process happens in people. "

Comment: the finding is logical. Any aging in germ cells, which is normal, cannot be allowed to influence the developing embryo. Only design can accomplish this.