genetics & evolutionary psychology or: once more with genetics

Genetics & Evolutionary Genetics & Evolutionary PsychologyPsychology

Or:

Once more with Genetics

BasicsBasics

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 Chromosomes, DNA, and GenesGenes

CellCellNucleusNucleus

ChromosomesChromosomes

Gene

ProteinProtein

Adapted from Adapted from Understanding Gene TestingUnderstanding Gene Testing, NIH, 1995, NIH, 1995

The DNA Double HelixThe DNA Double Helix

Adenine (A)Adenine (A)

Thymine (T)Thymine (T)

Cytosine (C)Cytosine (C)

Guanine (G)Guanine (G)

BasesBases

Sugar Sugar phosphate phosphate backbonebackbone

Base pairBase pair

Mitosis and MeiosisMitosis and Meiosis

MitosisMitosis

MeiosisMeiosis(germ cells only)(germ cells only)

2N2N

2N2N

NN

NN

NN

NN

Allele SegregationAllele Segregation

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

A aA a a aa a

A aA a a aa aA aA a a aa a

The Human GenomeThe Human Genome

23 pairs of chromosomes made of 700 million base pairs

30%70%

50,000–100,000 50,000–100,000 genesgenes

Extragenic Extragenic DNADNA

Repetitive Repetitive sequencessequences

Control regionsControl regionsSpacer DNA Spacer DNA

between genesbetween genesFunction mostly Function mostly

unknownunknown

Genetic CodeGenetic Code

A codon is made of 3 base pairs

64 codons total

1 codon (AUG) encodes 1 codon (AUG) encodes methionine methionine andand starts starts

translation of all proteinstranslation of all proteins

3 codons stop 3 codons stop protein protein

translationtranslation

61 codons encode 61 codons encode 20 amino acids20 amino acids

(redundant code)(redundant code)

U A A

A U G

Met

G C A

Ala

DNA Transcription and DNA Transcription and TranslationTranslation

mRNAmRNA

RibosomeRibosome

Growing Growing chain of chain of amino amino acidsacids

ProteinProtein

Nuclear Nuclear membranemembrane Cell Cell

membranemembraneDNADNA

Adapted from Adapted from Understanding Gene TestingUnderstanding Gene Testing, NIH, 1995, NIH, 1995

What does all this mean?What does all this mean?

Evolutionary PsychologyEvolutionary 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….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 PsychologyEvolutionary 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’tcon’t

Adaptions evolve to meet challenges in the environment

Humans are adaptive animalsBehavior etc. is adaptive

Inherited TraitsInherited Traits

Eye ColorBehaviorAltruism

– 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.

AltruismAltruism

Exercise - Essay by Lewis ThomasAssignment

– 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.”