Evolution and genetics

Question 1

What does DNA consist of?

Answer 1

Double helix: 2 backbones (phospheric acid + sugar) held by nucleotide base pairs:

Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)

A+T can pair or C+G

Question 2

What is the genetic code?

Answer 2

The information in DNA: Tells cells which type of protein/enzyme to make

Question 3

What does basepairs allow for?

Answer 3

1. replication during cell division

2. protein synthesis

Question 4

Describe protein synthesis

Answer 4

DNA –>mRNA –> proteins (20 amino acids)

through

1. transcription
2. translation

Question 5

Describe transcription (protein synth)

Answer 5

1. sequence of basepairs copied to mRNA
2. mRNA = single stranded - Uracil instead of Thymine –> A pairs with U
3. mRNA leaves nucleus –> enters cytoplasm –> connects with ribosomes

Question 6

Describe translation (protein synth)

Answer 6

1. mRNA –> amino acid
2. tRNA (transfer) transfers amino acid to ribosomes (specific tRNA for each amino acid)
3. tRNA+amini acid pairs up with mRNA as ribosome moves along mRNA strand
4. Each amino acid specified by codon (3 sequential mRNA (fx mRNA: GUA attracts tRNA: CAU) and tRNA transfers amino acid when bonded to chain of amino acids
5. Sequence of amino acids determines initial shape and function of proteins

Question 7

What is gene regulation?

Answer 7

How a gene (DNA code) is expressed or not (so how a protein is made or not)

responsible for long term developmental changes (iw song birds when they hear species song)

Question 8

What is homebox (hox) genes?

Answer 8

Large family of similar genes that direct formation of many body structures at embryonic development (38 hox genes)

Regulate development of a basic body plan

Question 9

Describe chromosomes

Answer 9

From chromatin, contain DNA: (humans have 23 pairs - 1 pair is the sex chromosom rest is autosomes)

Question 10

Describe mutations

Answer 10

= mistakes in DNA replications –> different alleles (gene)

Most mutation happens in regions of DNA not transcribed so have no effect

Question 11

What is phenotype and genotype?

Answer 11

Phenotype = what is shown (ie black fur)
Genotype = differences in genes (ie allel differences)

Behavioural genetics interested in how differences in genotypes –> differences in phenotype (heredity)

Question 12

What is adaption and the two methods used to identify it?

Answer 12

Adaption = beneficial mutation

1. Functional design: Trait respresent good design for function + trait should be evoked under appropriate conditions
2. Adaptive advantage: In environments resembling the ancestry one, individual lacking trait would be disadvantaged

Question 13

What is the social navigation hypothesis relating to depression?

Answer 13

• Depression evolved as context-evoked variety of psychological changes that enhanced fitness
• Energy is taken from everyday tasks and given to problem on hand (social rumination)
• Some motivation is facilitated
• fails to explain why depressive symptoms impair fitness-relevant social functioning

Question 14

What is Nettle’s argument against depression as evolutionary benefit?

Answer 14

• Pain is universal and acute - clinical depression is not universal and chronic
• Depression not evoked by appropriate triggers
• Fails to account for high prevalence of depression risk alleles in humans

Question 15

What is the pathogen host defence hypothesis in relations to depression?

Answer 15

• depression risk genes associated with immune response to infection (–> likely to enhance survival in ancestry environment)