How gene duplication events contribute to eukaryote diversity across the tree of life

Question 1

3 ways gene duplication can occur

Answer 1

unequal crossing over- one chromosome gets an extra copy of a gene, the other gets none
retroposition- reverse transcription of a gene
chromosomal/genome duplication- whole chromosomes/genomes get duplicated

Question 2

fundamentally- why are gene duplications important

Answer 2

provide raw material for natural selection

Question 3

4 outcomes of a gene duplication

Answer 3

• loss of duplicated copy (pseudogenes etc then eventually becoming just gene mush)
• increased gene dosage
• subfunctionalisation
  -neofunctionalisation

Question 4

ortholog vs paralog vs analog

Answer 4

ortholog- genes linked by speciation events- e.g. gene A in species 1 vs species 2
paralog- genes linked by duplication events, e.g. gene A and the new gene B
analog- unrelated but same function

Question 5

example of gene duplication in humans

Answer 5

amylase production- seems to have been duplications in populations with high starch diets
same deal with dogs, domestication > more starch > more amylase copies

Question 6

example of experimental work looking at the impact of gene duplications

Answer 6

see increased glucose transporter gene copies increase significantly under glucose-starved conditions

Question 7

another dog gene duplication examples

Answer 7

FGF4 acquisition associated with short little leggies!! in corgis and daschunds etc

Question 8

where have WGDs occurred

Answer 8

2 along vertebrates
3 in teleosts
4 in salmon
looooads in plants

Question 9

example of gene duplication in plant pathogens

Answer 9

oomycetes- see a lot of duplications in gene types like xyloglucanases, which break down plant cell wall components
this is good because if you have a bunch of stuff breaking these down in a slightly different way it gets harder for the plant to detect and respond to breakdown products
can also have duplications which block immune enzymes directly