Lectures 2&3 - Evolution of Ageing

Question 1

which 3 things characterise ageing? (hint loss of…. decrease…. increase of)

Answer 1

progressive loss of function
decreasing fertility
increasing mortality (with increasing age)

Question 2

in females, which two types of ageing are not in line with each other?

Answer 2

somatic ageing and reproductive ageing

Question 3

what is the proximate cause of the abrupt halt of fertility in women aged 45-50?

Answer 3

oocyte depletion

Question 4

is there any evidence for ageing genes?

Answer 4

no - genes are selected in survival

Question 5

name the 3 evolutionary theories of ageing linking extrinsic mortality and senescence?

Answer 5

mutation accumulation
antagonistic pleiotropy
disposable soma theory

Question 6

when does group selection of ageing genes for survival occur? what age?

Answer 6

younger age

Question 7

give an example of a genetic disease which is in line with the mutation accumulation theory

Answer 7

huntington’s disease

Question 8

in the mutation accumulation theory, which type of mutations, expressed at a young age, are severely selected against?

Answer 8

deleterious mutations

Question 9

which evolutionary theory of ageing is this describing? who came up with this theory?: deleterious mutations expressed only later in life are neutral to selection as their bearers have already transmitted genes to the next generation?

Answer 9

mutation accumulation by peter medawar

Question 10

give the order of the 3 evolutionary theories in which they were proposed, oldest to newest

Answer 10

1st: mutation accumulation
2nd: antagonistic pleiotropy
3rd: disposable soma

Question 11

give an example of a hormone in females which is in line with the antagonistic pleiotropy theory

give an example of a gene which can also be associated with this theory

Answer 11

oestrogen - good in earlier life, bad in later as can cause breast cancer\

p53/calcium related genes

Question 12

outline the theory of antagonistic pleiotropy, say why it occurs

Answer 12

mutations which are beneficial in early life but deleterious in later life don’t get selected out of a population
selection is less efficient in later life

Question 13

is selection of genes more efficient in early or later life?

Answer 13

early

Question 14

what is the key assumption made in the disposable soma theory regarding** the cause of ageing**?

Answer 14

ageing is caused by accumulation of damage

Question 15

in the disposable soma theory, long lived species have better…… and should accumulate damage more……

Answer 15

defences, slowly

Question 16

true or false, oxidative damage to protein accumulates with age?

Answer 16

true

Question 17

true or false, ROS production is higher in long lived species?

Answer 17

false, it is lower

Question 18

true or false, DNA repair is lower in long lived species?

Answer 18

false, it is higher as they are more resistant to stress

Question 19

name 2 stresses to DNA repair in long lived species?

Answer 19

H2O2 and paraquat

Question 20

in the hayflick limit, which type of cells have a limit?

Answer 20

mitotic cells like fibroblasts

Question 21

name the factors which may contribute to increased longevity in females rather than males?

Answer 21

XX heterogametic sex
mitochondrial inheritance
immunity better
sex hormones

Question 22

which evolutionary theory of ageing is a type of antagonistic pleiotropy but with more of a generic physiological focus?

Answer 22

disposable soma

Question 23

…… mortality eventually kills the majority of individuals and ageing is a ………. of evolution

Answer 23

extrinsic, by-product