DIMACS Seminar on Math and CS in Biology


Sex and the escape from mutational meltdown


Professor Robert C. Vrijenhoek, Director
Center for Theoretical and Applied Genetics, Rutgers University


The Waksman Institute, Room 1001
Busch Campus, Rutgers University


3:00 PM
Monday, March 6, 1995


Sexual reproduction in higher organisms is generally believed to be a mechanism that produces recombinational variability among an individual's offspring. This variability increases the scope for natural selection and adaptation in a spatially heterogeneous and temporally changing environment. Because asexual organisms lack recombinational variability, they are thought to be "evolutionary dead-ends." They may flourish temporarily, but will ultimately disappear because of evolutionary inflexibility. Studies of related sexual and asexual lineages of fish in the genus Poeciliopsis have generally supported this scenario. Evidence from mitochondrial DNA indicates that asexual lineages are short-lived and recent compared to sexual lineages. Also, examination of nuclear genes revealed that the asexual lineages have accumulated numerous potentially deleterious mutations that eventually will lead to a "mutational meltdown." We have recently discovered an escape from this asexual doomsday scenario, in the form a new sexual species that had asexual ancestors. The genealogy of this new species is traced over what we assume to be at least one hundred thousand generations with nuclear and mitochondrial genetic markers.

Upcoming talks

March 13, Spring break
March 20, Protein Structure Workshop
March 27, Dr. Sampath Kannan, U. Penn
April 3, Dr. Donald Beaver, Penn State Univ.

Document last modified on February 28, 1995