Lecture 6- Genomes

Question 1

when was the first human genome sequenced

Answer 1

2000

Question 2

how many base pairs in the human genome

Answer 2

3 x 10^9 base pairs

Question 3

what percentage of the human genome codes for proteins

Answer 3

3%

Question 4

what percentage of the human genome is regulatory genes

Answer 4

10%

Question 5

what percentage of the human genome is junk

Answer 5

85%

Question 6

transposons

Answer 6

sequences of DNA that can move in the genome
(mobile genetic elements)

Question 7

retrotransposons

Answer 7

produce RNA, then reverse transcribed into DNA and then inserted into genome

Question 8

what are transposons agents of

Answer 8

evolution and disease

Question 9

what are transposons remnants of

Answer 9

retrovirus in DNA

Question 10

characters that prevent transposition

Answer 10

methylation (favoured to prevent mutation) and small interfering RNAs (produced by some transposons)

Question 11

process of the creation of new genes

Answer 11

1. duplication in non coding regions creating long string of 3 AAs
2. overtime, changes in base sequences (mutations) causes tagging as secretory
3. translocation brings sequence near promoter region

Question 12

example of new genes in fish

Answer 12

fish living in polar seas have antifreeze glycoproteins

Question 13

evolution of the placenta

Answer 13

syncitins (needed for the placenta) once coded for the envelope of a retrovirus
overtime, mammals have reused these genes to develop the placenta and regulate gene activity

Question 14

horizontal gene transfer

Answer 14

transfer of genetic material from an organism to another organism that is not it’s offspring
-mainly in prokaryotes
-in multicellular organisms, involves parasite or symbiote

Question 15

limitations of horizontal gene transfer

Answer 15

minor source of genetic variation

Question 16

implications of horizontal gene transfer

Answer 16

can lead to adaptations
e.g spodoptera moth acquired an immune barrier through a virus that lives in a parasitic wasp
e.g genes involved in carotenoid biosynthesis acquired from fungus

Question 17

how many groups of genes are necessary to be an animal

Answer 17

25

Question 18

environmental DNA

Answer 18

extraction of sequences without an organism mainly from soil, water or air
-non invasive observational technique
-requires careful amplification and bioinformatic identification

Question 19

what percentage do human genomes differ from each other

Answer 19

0.1% (3 million bases)

Question 20

how many nuclear muations are present that aren’t present in our parents

Answer 20

70

Question 21

example of how genetic variation is severely underestimated

Answer 21

910 individuals of recent African decent had 10% more DNA than in the reference genome including some being protein encoding genes

Question 22

evidence of natural selection in humans: Tibetans

Answer 22

mutation of EPAS1 gene (regulated RBC production) found in 87% Tibetans (lived in high altitudes with 40% less oxygen) compared to only 9% Han Chinese shows clear genetic evidence of natural selection in humans adapting to low oxygen environments

Question 23

evidence of natural selection in humans: Bajau people in S-E Asia

Answer 23

able to dive for long periods
-selection on PDE10A gene= larger spleens (resevoir of RBC)
-selection on BDKRB2 gene= involved in diving reflex

Question 24

how many genes are involved in skin colour

Answer 24

atleast 15 genes

Question 25

does skin colour correlate with other traits

Answer 25

no