Textbook Module 1.2 Genetics and Behavior

Module 1.2 Genetics and Behavior   January 20, 2015

PLEASE READ THE ENTIRE MODULE 1.2 FROM THE TEXTBOOK AND THEN READ THESE NOTES. PAY PARTICULAR ATTENTION TO THE MATERIAL IN RED THAT IS BELOW. THE RED TEXT MAY BE USED FOR QUIZ/TEST QUESTIONS.  

Mendelian Genetics

The book concludes that it is both Nature and Nurture since the Module begins with the statement "Everything you do depends on both your genes and your environment."

The evidence provided for this statement is facial expressions. What kind of observations led to the conclusion about facial expressions?  Other behaviors listed are intelligence, sexual orientation, alcoholism and weight gain.  Could you provide evidence for both genetic and environmental influences on these behaviors?

 I understand that many of you may have taken Biology some time ago, so you may be unfamiliar with Mendelian Genetics. I've tried to provide a brief but effective re-introduction, starting with this video.


A much broader view of Figure 1.7 and Figure 1.9 
Here you will be reminded that living tissue is made up of cells. Every cell has a nucleus, Every nucleus contains materials for the replication of the cell, genes. Genes are made up of DNA.  RNA is used to replicate the gene from the DNA.
 
According to the text, Genes are units of heredity that maintain their structural identity from one generation to another. Genes are defined as a portion of a chromosome which is composed of the double-stranded molecule DNA. Here's a movie to help visualize this.  (Please watch the videos SEVERAL times in order to answer the questions in red below.)

Genes are reproduced through a process of DNA replication and DNA transcription.  A strand of DNA serves as a template for the synthesis of RNA, a process called transcription.

From the Videos above answer the following questions.
1. could you explain how the following terms differ from one another?
DNA,  Chromatin, Chromasomes, Histones, Nucleosome

2. How many molecules of DNA are synthesized by RNA.

Once there is a single strand of messageRNA or mRNA (copied DNA), the strand leaves the nucleus and is joined to ribosomes where amino acids sequences produce proteins. This process is translation.

Genes can be dominant, recessive or intermediate.  Here's an explanation using what Mendel used, peas.

From the Video define- allele, genotype and phenotype.
 The list of traits given at the beginning of the chapter include intelligence, sexual orientation, alcoholism and weight gain. Now that you have a clearer understanding of genotype and phenotype, do you believe there is a genetic basis for intelligence, sexual orientation alcoholism or weight gain.  Be able to explain your answer?


Genetic Changes

Genes can change and therefore the transcription by mRNA will be altered as well as translation of proteins as the final outcome.

Mutations of the gene (incl. duplication and deletion)
Epigenetics- Various experiences can turn a gene on or off.  Evidence of epigenetic effects come mainly from animal studies, several of which were described on pg. 12.

What did Godfrey et al, 2007 discover about obesity and heart disease?
What did Weaver et al, (2004) find out about the effects of maternal care on stress levels of rat pups?

How does an experience modify gene expression?

Heredity and Environment

Evidence about the influence of heredity and environment often come from twin studies. Why?

What does it mean to be a monozygotic or dizygotic twin?

Evolutionary Psychology

Define the terms: altruism, kin selection and reciprocal altrusim