Genetics (L18-19)

Question 1

Define microbiome

Answer 1

sum total of the genes carried by micro-organisms commensal with humans”

Question 2

define microbiota

Answer 2

species of micro-organisms commensal with humans”

Question 3

define diversity (+types)

Answer 3

number and abundance distribution of distinct types of organisms
• Alpha diversity (within samples)
• Beta diversity (between samples from same habitat in different subjects)

Question 4

functions of bacteria in body

Answer 4

o Extracting energy from food

o Regulating immune (protecting from disease)

Question 5

2 types of bacteria

Answer 5

o Commensal microbes

o Potential pathogens (exists as low pops but increase = bad

Question 6

explain getting variation in microbiota but microbiome similar

Answer 6

= functional locations

Question 7

why would proteobacteria be higher in italisna than HG

Answer 7

maximising metabolic energy extraction from ingested plant material

Question 8

Explain decrease in diversity b/w micro biome in hg, agri and modern humans

Answer 8

• Depending on diet= shfits b/w HG, agric + modern

o Relates to ability to extract energy + immune system

Question 9

define phenotypic plasticity

Answer 9

variation, under environmental influence, in the phenotype associated with a genotype

Question 10

define epigenetic

Answer 10

modifications resulting in altered regulation of gene expression without involving changes in the DNA sequence (inherited; chromatin modification)

Question 11

diff/ genetics and epigenetics

Answer 11

• Different to genetic variation (a vs b) - changes to DNA itself
• Where epigenetics= way DNA is packaged (how DNA is accessed)

Question 12

define epigenome

Answer 12

Epigenetic marks along the genome

Question 13

describe epigenetic in Stem cells

Answer 13

•Blue= promotor region in neuron cell
o Expression associated with neuron
o // this promotor area= tightly wound in liver cell as doesn’t require expression

Question 14

describe chemical modification general for histones

Answer 14

• Tail has chemical modification: phosphorylation, methylation (some= closed), acetalization (open)
• Chemical structures added depend whether open or closed

Question 15

explain methylation

Answer 15

adding methane
• If island heavily methylated, proteins will attach and prevent transcription factors to access site (out competes)
o When cytosine not methylated= able to be transcript

Question 16

2 ways to turn off genes

Answer 16

• Histone Tag
o Packaging: Modifying chemical tail (limits protein access)
• CpG modification
o Methylation in CPG island in promotor islands of genes (also limits protein access)

Question 17

explain epigenetic of twins as they get older

Answer 17

• Concordance rate decreases with age
o Genetic influence prominent earlier > environment alters
o Epigenetic profile changes

Question 18

explain relationship b/w epigenome, micro biome, immune response

Answer 18

• metabolites released by bacteria acts to change epigenetic profile of DNA of naive t cell to drive towards particular type of t cell
o // disruption of microbiome= affect expression + tolerance of particular bacteria