Scientists
aren’t exactly sure how many new mutations crop up each generation
in humans—for years, the standard estimate was round 100-200, but
one
2011 study,
using whole genome information from two families, has put it at about
30-50. And the rate of mutation is more than a curiosity: Seeing how
many mutations separate us from cousin species and multiplying that
by the rate of change is one way scientists measure the time since we
diverged from each other—a “molecular clock.” So that new,
lower mutation rate—30-50 changes per generation—implies that our
common ancestor with chimps was not 5 million years ago, as had been
thought, but 7 million years. (For
-
A Universal Cancer Treatment?
A medicine that disrupts the DNA replication of cancer cells may be within reach.
-
After 100 Years of Research, Autism Remains a Puzzle
One geneticist is determined to piece together the causes.
-
Embryo Cells Set Patterns for Growth by Pushing and Pulling
Patterns that guide the development of feathers and other features can be set by mechanical forces in the embryo, not just by gradients of chemicals.
-
Life’s First Peptides May Have Grown on RNA Strands
RNA and peptides coevolving in the primordial world might have jointly served as a precursor to the modern ribosome.
-
The Race to Protect Sweet Corn
Breeding a variety that can withstand disease and taste better, too.