Why do ‘normal’ embryos still fail?
Even chromosomally normal embryos often fail, and at the 2023 Activated Egg Symposium, David Keefe offered a surprising explanation. Ahead of this year’s symposium on November 6, we’re revisiting him and Oliver Rando, two of our most talked-about speakers from 2023.
DAVID KEEFE, MD | NYU Langone (2023)
Why do so many human embryos fail, even when they’re chromosomally normal?
Dr. Keefe traced the answer to telomeres, the protective caps on our chromosomes, and their surprising partnership with “jumping genes” called retrotransposons. He proposed that the early embryo rapidly rebuilds its telomeres without telomerase, and may even rewrite parts of its own genome along the way. He also drew a striking line between tumor and embryo biology:
“Cancers are not wildly innovative; they co-opt things that were developed.”
And on the power of the egg itself:
“If you take a 40-year-old woman and you give her a 20-year-old egg, she’s got the 20-year-old’s fertility.”
▶ Watch Dr. Keefe’s talk “Retrotransposition and early embryo development”
OLIVER RANDO, PhD | UMass Chan Medical School
Epigenetic Contributions of Sperm to the Next GenerationCan a father’s diet shape his children’s health?
Dr. Rando walked through more than a decade of his lab’s work showing that it can, at least in mice, and that sperm themselves carry the message. Males fed a low-protein diet sired offspring with altered cholesterol metabolism, an effect that held up even through IVF. Rando traced much of this information to small RNAs that sperm pick up as they mature in the epididymis, some of which regulate gene expression in the earliest stages of embryonic development.
“The epigenetic information carriers listen to the world and sometimes make it into the next generation.”
He also made the provocative case that most published measurements of sperm chromatin may have been skewed by contamination, and candidly laid out the open questions in his own model. It was a talk as thought-provoking as it was rigorous.
“They’re really just delivering a whisper of RNA to the embryo.”
REGISTER NOW FOR THE 2026 SYMPOSIUM
“Unique Human Egg Activation Pathways”
Friday, November 6 · MIT Endicott House · Dedham, MA
The 2026 program brings together leading investigators to examine human egg activation from multiple perspectives—from oocyte development and fertilization to early cleavage stages, genome stability, and stem cell-derived models.
