Transcript Weird animal genomes, sex and the future of men Professor Jennifer

Welcome to Open Lecture
“Weird animal genomes, sex and
the future of men”
Professor Jennifer A. Marshall Graves
Fellow of the Australian Academy of Science
Professor Jennifer A. Marshall Graves
Fellow of the Australian Academy of Science
Distinguished Professor, La Trobe University
Professor Emeritus, Research School of Biology, ANU
Thinker-in-Residence, University of Canberra
Professorial Fellow, University of Melbourne
Jenny received her BSc and MSc from the University of Adelaide and a PhD from the
University of California at Berkeley. She ran “JennyTech Labs” at La Trobe University for
many years before moving to ANU, where she headed the Comparative Genomics Group
in the Research School of Biology. After 10 years at ANU, Jenny has now returned to La
Trobe as Distinguished Professor. She founded and directed the multi-node ARC Centre of
Excellence in Kangaroo Genomics. She has edited four books and 400 research articles.
Jenny has received many honours and awards, including the Academy’s Macfarlane
Burnet medal in 2006 and an Order of Australia (AO) in 2010, and is a 2006 L’OrealUNESCO Laureate. Jenny is a Fellow of the Australian Academy of Science, serving as
Foreign Secretary 2006-10, and currently as Secretary of Education.
Professor Jennifer A. Marshall Graves
Fellow of the Australian Academy of Science
Research and Professional Interests
Jenny and her talented research group made seminal contributions to the understanding of
mammalian genome organization and evolution, exploiting the genomic differences of
Australia’s unique animals as a source of variation to study highly conserved genetic
structures and processes. Their studies of the chromosomes and genes of kangaroos and
platypus, devils (Tasmanian) and dragons (lizards) has shed light on the organization,
function and evolution of mammalian genomes. Her work on sex and sex chromosomes in
“weird animals” has led to influential new theories of the origin and evolution of human sex
chromosomes and sex determining genes, as well as the evolution of epigenetic silencing
in mammals.
Jenny has been involved in international comparative gene mapping and genomics from
the 1980s. As co-chair and co-editor of the Comparative Committee of the Human Gene
Mapping workshops from 1987, she promulgated the value of comparison of gene maps,
and the special value of including distantly related vertebrate species. As Foundation
Director of the ARC Centre of Excellence in Kangaroo genomics, she led movements to
fully sequence the genomes of Australian mammals (kangaroo and platypus), and now
participates in major international vertebrate genome sequencing projects.
Weird animal genomes, sex and the future of men
Professor Jennifer A. Marshall Graves
Summary:
The human X is a middle-sized chromosome, rich in “brains-and-balls” genes involved in reproduction and
intelligence (often both), and thought to have had a major role in human evolution. The tiny Y is a genetic
wasteland – full of genetic junk and bearing only 45 genes, most of which are active only in testis. Human
sex chromosomes are nothing but trouble. The X and Y don’t pair very well at male meiosis (causing
infertility), the dosage difference of the X between the sexes requires compensation, its unpaired state in
males causes sex linked diseases, and translocations of the terminal SRY leads to sex reversal. Are they
weird because they work better, or is it the result of some horrible evolutionary accident?
To follow the evolution of the human X and Y, we compare the chromosomes, genes and DNA in distantly
related mammals, and even birds and reptiles. The genomes of Australia’s unique kangaroos and platypus,
now completely sequenced, are a goldmine of new information. Kangaroo sex chromosomes reveal the
original mammal sex chromosomes, while the bizarre platypus sex chromosomes (more related to those of
birds) tell us that human sex chromosomes are relatively young. The human X and Y evolved from an
ordinary autosome pair only about 166 million years ago as the Y degraded rapidly. Reptiles display all kinds
of sex chromosome systems as well as temperature dependent sex, and reveal that the function of triggering
sex determination different regions has been taken on by different regions of the very conserved amniote
genome.
At this rate of degradation, the human Y chromosome will disappear in just 5 million years. If humans don’t
become extinct, new sex determining genes and chromosomes will evolve, maybe leading to the evolution of
new hominid species.
Weird animal genomes, sex
and the future of men
Professor Jennifer A. Marshall Graves
Fellow of the Australian Academy of Science