Notatki Danniego part 6

Question 1

Huntingtons disease causes … damage

- shows effects in …

Answer 1

brain

middle age

Question 2

Incomplete dominance pedigree:

Answer 2

-> Dominant mother has son without phenotype but then passes allele on to children

Question 3

Variable expressivity:

Answer 3

-> Gene can be expressed more or less in certain individuals

Question 4

Quantitative genetics 2 groups:

Answer 4

• > Continuous

- > Discreet

Question 5

Quantitative genetics: soldier height:

Answer 5

Mean soldier height:
1914 - 5ft 7
1996 - 5ft 8

Max soldier height:
1914 - 6ft 1
1996 - 6ft 5

• > Must be environmental factors as 2 generations isn’t long enough to have a genetic change in height that much
  - > Galton’s height diagram showed that tall parents had taller children and vice versa
  - > He also observed, when parents are taller that the mean, their children tend to be shorter than them

Question 6

Quantitative genetics: tomatoes:

Answer 6

• > Tomatoes used to be small, green and hard, weren’t really eaten until 1800s
  - > Bred them for sweetness, juiciness, softer

Question 7

Quantitative genetics: maize:

Answer 7

• > Maize yield has gone up around 8x since 1876
  - > feeds most of the world
  - > fertilizer & quantitative genetics
  - > accumulation of genes that increase size

Question 8

Wheat cross:

Answer 8

red seeds X white seeds 2 loci
P1: AABB X aabb
F1: All AaBb (pink)
self fertilise

F2:
1 Red
4 Light red
6 Pink
4 Light pink
1 White

The amount of red depends on the amount of red alleles compared to white alleles
e.g.
AABB   red         4+
AaBB   light red 3+
AaBb   pink        2+
Aabb   light pink 1+
aabb   white       0+
-> depend on number of + -> continuous character

Question 9

Quantitive inheritance 5 loci

Answer 9

green post-it (2pg)

Question 10

Heritability equation

Answer 10

Genetic variance Vg divided by phenotypic (total) Variance Vp

H^2 = Vg/Vp

Question 11

Heritability - about

Answer 11

• > Heritability is a proportion
  - > can change genes or environment
• > The proportion of the total variation in the population that is due to genetic variation

Question 12

Achillea plant

Answer 12

• > Grows at a range of altitudes:
  - sea level
  - medium
  - 10,000 ft Mountains
  - > Cross breeds from different breeds as they have a variation in height
  - > You find heritability as height is passed on
• > Plants that usually grow well at low altitudes can grew worse at lower altitudes but better at higher than medium
  - > different norms of reaction

Question 13

Heritability equation2

Answer 13

H^2 = Vg/Vp
Vp = Vg + Ve + Vge

H^2 = Vg/(Vg + Ve + Vge)

Question 14

Broad sense of heritability

Answer 14

-> Plant and animal breeders need the NARROW sense of heritability

Vg = Vg + Ve + Vge

Additive ++ = 2 cm +- = 1 cm – = 0 cm
Dominance ++ = 2 cm +-= 2 cm – = 0 cm
Interaction ++++ = 2 cm +++- = 1-2 cm ++– = 0 cm

Question 15

NARROW sense heritability only uses …

Answer 15

Additive inheritance
H^2 = Vg/Vp
-> Never been used for human characteristics

Question 16

Covariance

Answer 16

tendency for parents and offspring to vary together grom normal distribution

4 parents and offspring are always same height
-> correlation coefficient of 1. => r = 1

Father	Son		Covariance
1.4		1.6		-0.2^2 =	   0.04
1.5		1.7		-0.1^2 = 	   0.01
1.6		1.6		0 x –0.2 =  0.00
1.7		1.9		0.1^2 =        0.01
1.8		2.2		0.2 x 0.4 = 0.08
						          = 0.14
Mean father= 1.6
Mean son= 2.2

Covariance = difference of father from mean & difference of son from mean

Covariance = 0.14

Simplified (?) of correlation coefficient:

Covariance (fathers & sons) / [sd (fathers) x sd (sons)]

Question 17

Simer fox experiment (?)

Answer 17

• minus “aggressive” foxes & plus “tame” foxes
• Usually incredibly aggresive/scared towards humans but a tame, domesticated species has been bred
• Dmitry K Belyaev (?) in the 50s
  - > bred the 1% most tame foxes over generations
  - > is generations (?)
• changed morphology
  - > floppy ears, piebald coat, dog-like bark
• domestication gene associated with melanin & adrenaline
  - > less adrenaline, less fight or flight

Question 18

Neotorous (?)

Answer 18

(?) retains, juvenile characteristics in adulthood

-> pyreneon mountain dog (?)

Question 19

Average drosophila no. of (?) is …

Answer 19

(?)
-> select & breed only flies with 467
-> next gen average 45, gain of 5
Narrow sense heritability 5/6 = 0.83
High heritability
-> Same but new mean is 43, gain of 3
3/6 = 0.50. intermediate heritability

R = 4^2 S

Question 20

Heritability of schizophrenia:

Answer 20

Identical twins 48%
Siblings 9%
Parents 6%
General pop. 1%

Twins also have a high degree of environmental similarities

Question 21

Two embryos fuse -

Answer 21

chimaera

Common in foetuses, can have 2 (?) sers of genes

Question 22

Monochorionic twins (?)

Dichorionic twins (?)

Answer 22

early split in womb, share a placenta - causes problems

split later

Question 23

Uniwersal common ancestor around … BC

MRCA -

Answer 23

3000

Most Recent Common Ancestor

Question 24

Inbreeding can encome (?) genetic disease as higher risk of getting double recessive alleles

Answer 24

/// I don’t understand what’s this “setting in a plant” thing////

Question 25

Inbreeding flow diagram

Answer 25

ADD A PICTURE OF THIS DIAGRAM

One locus, A
4 alleles : 1, 2, 3, 4

Brother I & sister II mate

What is increased chance of homozygosity by (?) for Ai in child III?