EP 253: The genetics of brain size, growth, and aging with Andrew Jackson of the University of Edinburgh

This week on The Genetics Podcast, Patrick is joined by Dr. Andrew Jackson, Programme Leader at the MRC Human Genetics Unit at the University of Edinburgh. They discuss how his lab discovered that gain-of-function DNMT3A mutations cause both microcephalic dwarfism and an accelerated aging syndrome, and what that reveals about the shared biology of growth and aging.Show Notes0:00 Intro to The Genetics Podcast00:59 Welcome to Andrew01:34 The origins of Andrew's work linking brain size and aging02:54 The genetics of mammalian size range and epigenetic factors regulating growth05:02 How DNMT3A mutations causing dwarfism led to discovering an accelerated aging syndrome09:46 Cell number rather than cell size as the shared driver of growth and aging13:07 Whether brain size within humans actually predicts cognitive ability15:20 Why intellectual disability has far more known genes than dwarfism19:26 Discovering ribonuclease H2's role in DNA repair, and its unexpected link to cancer 23:35 Why studying rare monogenic diseases reveals broader biology26:59 Andrew's next research questions on aging, cancer, and mutation biology28:42 Why humans, model organisms, and cell assays each have a role31:00 Somatic mosaicism's growing role in aging and disease beyond cancer36:11 Closing remarksFind out more:Mentioned studies from Andrew’s lab: https://www.nature.com/articles/s41588-026-02633-8https://www.nature.com/articles/s41588-018-0274-x