Module 7 - Part 1

Question 1

Environment (& types)

Answer 1

Anything external to the genome
- internal environment (eg. hormones)
- external environment (eg. temp)

Question 2

Phenotype

Answer 2

Is an individual’s observable traits
- genetic contribution = genotype
- some are largely determined by environmental factors

Question 3

Male pattern baldness
(genes x internal environment - hormones)

Answer 3

• baldness allele expressed in men & women (autosomal)
• expression affected by levels of testosterone & dihydrotesterone
• trait influenced by sex but not limited to sex (ie. high levels in women can = hair loss in women)

Question 4

Lactation
(genes x internal environment - hormones)

Answer 4

• gene required = autosomal but NOT expressed in men
• sex-limited trait
• only expressed in women/biological female (XX) who are lactating

Question 5

Coat colour on the Siamese cat
(genes x external environment - temp)

Answer 5

• siamese allele Cs - temp sensitive allele of the tyrosine gene
• SNP: G-A transition in exon 2
• enzyme active at extremities - normal pigment (brown)
• enzyme inactive at core body temp (white)

Question 6

Temperature sensitive alleles

Answer 6

Gene variants that allow normal protein folding function at permissive temp (usually recessive)
- lower temp for siamese cats

Question 7

Altered func. temp sensitive alleles

Answer 7

Protein misfolding or unfolding at non-permissive/restrictive temp
- high temp for siamese cats

Question 8

Roberts Syndrome (aka-pseudo-thalidomide syndrome)

Answer 8

• due to genetics (not environment)
• autosomal recessive mutation in ESCO2: sister chromatids not held together = improper alignment of chromosome (aneuploidy & cell death)

Question 9

Roberts syndrome phenotype (4)

Answer 9

• deficits in all 4 limbs
• pre&post natal growth delays
• microcephaly
• bilateral cleft lip & palate

Question 10

ESCO2

Answer 10

establishment of sister chromatid cohesion N-acetyltransferase 2
- enzyme that acetylates cohesion: protein required to “glue” two sister chromatids together during mitosis

Question 11

Genes x external environment - drugs

Answer 11

1959-1961: increase in cases of phocomelia in Can, Australia, europe
- cause: thalidomide: prescribed for countering the effects of morning sickness
- symptoms similar to Roberts

Question 12

phenocopy

Answer 12

an environmentally induced phenotype that is similar to a genotypically-determined phenotype (ie. Roberts & thalidomide)

Question 13

intercalculate

Answer 13

to insert something between the layers of a highly ordered structure
- thalidomide binds to a regulatory element called the GC box: bound by SP1
- it intercalculates DNA

Question 14

Risk factor

Answer 14

something that increases the chances of developing disease
- not causative

Question 15

Causative agent

Answer 15

most often biological agent that causes disease
ex. AIDs, caused by HIV

Question 16

Non-modifiable risk factors

Answer 16

have no control over these
- genetics
- biological sex
- age
- race (due to social constructs)

Question 17

Modifiable risk factors

Answer 17

you can control these
- physical inactivity
- diet
- alcohol
- smoking

Question 18

Gene ontology (GO) terms grouped by

Answer 18

1. income per dependent - cell adhesion, development
2. parents education - tissue development programs, cell differentiation
3. family adversity - immune cell development, func & regulation