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Gene co-option. the process by which a trait/gene changes function; the gene has been co-opted to do a new job. Gene Co-option. Inheritance of Acquired Characteristics. Epigenetics turns on/off genes. http://cnx.org/content/m26565/latest/graphics35.jpg.
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Gene co-option • the process by which a trait/gene changes function; the gene has been • co-opted to do a new job
Epigenetics turns on/off genes http://cnx.org/content/m26565/latest/graphics35.jpg
Epigenetic patterns are heritable, but can be changed by the environment more easily than can genes Jirtle and Skinner, 2007, Nature Reviews Genetics
Epigenetics and behavior http://learn.genetics.utah.edu/content/epigenetics/rats/
Darwin’s finches Patel, 2006, Nature, 442:515-516
The BMP4 GeneSame protein Different mRNA levels in different species
A second gene… CaM Beak morphology is skeletal and related to differences in CaM expression during development Abzhanov et al., 2006, Nature, 442:563-567
Up or down regulation of two genes can create a wide variety of 3-D shape Abzhanov et al., 2006, Nature, 442:563-567
What explains Darwin’s finches? • Difference in gene expression (high, moderate, or low) for two genes. What are the possible mechanisms? • Switch? • Gene duplication? • Epigenetics?
Mutations are accidents within the cell during DNA replication and during meiosis • These mutations happen with no regard to what is happening to the organism or to what the organism needs… • That doesn’t mean that some mutations aren’t lucky! • Mutation creates new alleles that can be selected for or against
Mutation is important in evolution because it is THE source of new alleles
Gene Poolall of the alleles in all of the gametes of the population • Concept works for sexual reproducers • Alleles can unite randomly (as if swimming), or they can unite non-randomly if there is mating preference
Dawkins on “Gene Pools”“The very idea of a gene pool has no meaning if there is no sex. 'Gene Pool’ is a persuasive metaphor because the genes of a sexual population are being continually mixed and diffused, as if in a liquid.
-Richard Dawkins,The Ancestor's Tale , page 432 Bring in the time dimension, and the pool becomes a river, flowing through geological time..."