PSB-2000 Study Guide - Phenylthiocarbamide, Heritability, Twin
Document Summary
A gene for a bitter receptor: homozygous recessive (tt): can"t taste ptc, heterozygous (tt): it tastes somewhat unpleasant, homozygous dominant (tt): it tastes horrible, lots of behavioral implications including taste in foods, likelihood to smoke, drink, etc. A very debatable question: prenatal environment: twin studies: mz twins share chorion and blood supply (ie, more similar prenatal environment compared to dz twins) so could be genetics or could be prenatal environment, adoption studies: biological children of low iq or mentally ill parents tend to have similar problems even if raised by great adoptive parents could be genes but could be a reflection of poor prenatal environment. How could genes affect behaviors: altering neurotransmitter systems and other chemicals, thus how an individual responds to the environment, reducing gene expression to increase metabolism and regulate fate, altering physical appearance and thus how the environment responds to the individual.
