Week 3. Natural Selection and Behavioral Genetics

September 11th

Before going any further..... What do we mean by "Nature" and how has this been shaped through evolution. In order to study behavior as a phenotype we must understand how evolution shapes phenotypes through natural selection.

Sinervo chapter 2,3,4

Like natural selection, artificial slection alters gene frequencies in a population. Repeated examples of animal domestication results in similar phenotypes. The geneitc architecture of domestication is currently under investigation.
Trut (1999) Early Canid Domestication: The Farm-Fox Experiment American Scientist 87:159-169.

For a brief and entertaining historical account of Darwin's "Origin of Species" try reading
Keynes, RD (1996) Steps on the Path to the Origin of Species. J. Theor. Biol. 187, 461-71

for fun: when and where were our pets domesticated?
Leonard et al (2002) Ancient DNA Evidence for Old World Origin of New World DogsScience 198:1613-1616.
Driscoll et al (2007) The Near Eastern Origin of Cat DomesticationpossiblyScience 317:519-523

September 13th

When we search for the proximate factors for behavioral causes, we naturally start with genes. Our understanding of how genes influence behavior has been advanced both by studies of wild populations and model organisms in the lab. While early studies identified single genes of large effect we now know that the genomic architecture of many behaviors is complex.

While much of our understanding of behavioral genetics derives from Drosophila mutants and white lab mice, the examples natural behavioral phenotypes affected by naturally occurring allelic variation are by far the most exciting. This excitiement comes at a cost and one must weigh the relative benefits and choose experimental systems wisely.

Sinvero chapter 2
NY-Times 2005
NY-Times 2007
Sokolowski (2001) Drosophila: Behavior meets Genetics. Nature Genetics 2:877-892.
Nair & Young (2005) Vasopressin and Pair-Bond Formation: Genes to Brain to Behavior. Physiology 21:146-152.

To find human genes known to strongly influence behavior check out the NIH website Online Mendelian Inheritance of Man and look up behavior.
Fink, S., Excoffiel, L., Heckel, G. (2006) Mammalian monogamy is not controlled by a single gene PNAS 103:10956-10960.
Young, L.J., & Hammock E.A.D. (2007) On switches and knobs, microsatellites and monogamy TIG 23:209-212.

More Extra:

--Strains of mice that show characteristic patterns of behavior are critical for research in neurobehavioral genetics. Crabbe (from OHSU) and colleagues performed replicated behavioral tests in several labs across the country to validate these assumptions (Wahlsten_2003).
--It is widely acknowledged that the nature of the maternal care a child receives can have long-term reper-
cussions, and that children raised in deprived environments can have severe cognitive and behavioural
difficulties that last into adulthood. The mechanisms underlying these effects are one of the most exciting areas of research right now (in my opinion). The rat model of maternal behavior offers us our first understanding of the possible mechanisms that underlie this effect (Meaney and Szyf, 2005). Surprisingly, it is the protien structure of the chromosome, the chromatin, that codes this affect. In a parallel study, researchers have identified a specific allele of a neuotransmitter receptor that may affect a similar plasticity of behavioral phenotype (Hariri et al., 2002) that might even extend to humans (Champoux et al., 2004)