Genetics & Evolutionary Psychology Or: Once more with Genetics

Basics Genotype – The genetic makeup, as distinguished from the physical appearance, of an organism or a group of organisms Phenotype – The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.

Chromosomes, DNA, and Genes Cell Nucleus Chromosomes Gene Protein Adapted from Understanding Gene Testing, NIH, 1995

The DNA Double Helix Adenine (A) Thymine (T) Cytosine (C) Guanine (G) Bases Sugar phosphate backbone Base pair

Mitosis and Meiosis Mitosis Meiosis (germ cells only) 2N 2N N N N N

Allele Segregation Alleles: variant forms of the same gene (A a) A a a a A a a a A a a a

The Human Genome 23 pairs of chromosomes made of 700 million base pairs 30%70% 50,000–100,000 genes Extragenic DNA Repetitive sequences Repetitive sequences Control regions Control regions Spacer DNA between genes Spacer DNA between genes Function mostly unknown Function mostly unknown

Genetic Code A codon is made of 3 base pairs 64 codons total 1 codon (AUG) encodes methionine and starts translation of all proteins 3 codons stop protein translation 61 codons encode 20 amino acids (redundant code) UA A A UG Met G C A Ala

DNA Transcription and Translation mRNA Ribosome Growing chain of amino acids Protein Nuclear membrane Cell membrane DNA Adapted from Understanding Gene Testing, NIH, 1995

What does all this mean?

Evolutionary Psychology Evolutionary psychologists believe that behaviour is strongly influenced by inherited factors, and that every human being acts (consciously, but mostly unconsciously) to enhance their inclusive fitness - i.e. to increase the frequency and distribution of their genes in future generations.

Or…. The ultimate goal that the mind was designed to attain is maximizing the number of copies of the genes that created it. - Steven Pinker

Evolutionary Psychology natural selection designed our minds for life in an environment resembling the African savannah It is only about 10,000 years since humans first started growing their own food Environment of Evolutionary Adaptedness EEA. The EEA does not refer to some short period of time in our past. It refers to an array of factors that have influenced inclusive fitness during our evolution over the last 200,000 years

con’t Adaptions evolve to meet challenges in the environment Humans are adaptive animals Behavior etc. is adaptive

Inherited Traits Eye Color Behavior Altruism – Unselfish concern for the welfare of others; selflessness. – Zoology. Instinctive cooperative behavior that is detrimental to the individual but contributes to the survival of the species.

Altruism Exercise - Essay by Lewis Thomas Assignment – Is altruism a genetic predetermined factor. Or is it, in the words of Richard Dawkins. “[that] we are born selfish. If we find that human behavior is altruistic, we will be faced with something that needs explaining.”