Populations and Genes

Question 1

D: Crude birth rate

Answer 1

number of births per unit of person-time. The world average crude birth rate is around 18.5 births per 1000 person-years.

Question 2

D: Crude death rate

Answer 2

number of deaths per unit of person-time. The world average crude death rate is around 7.8 births per 1000 person-years.

Question 3

D: Crude rate of natural increase (or decrease)

Answer 3

Crude rate of natural increase (or decrease) = crude birth rate – crude death rate.

The world average crude rate of natural increase is 10.7 per 1000 person years.

Question 4

D: Total fertility rate

Answer 4

Total fertility rate represents the total number of babies per average reproductive lifetime.

The total fertility rate in England and Wales is approximately 1.76 births per women’s reproductive lifetime.

Question 5

D: Gross reproductive rate

Answer 5

Gross reproductive rate represents the total number of daughters per average reproductive lifetime.

The England and Wales gross reproductive rate is approximately 0.86 daughters per women’s reproductive lifetime (= proportion of female births x total fertility rate).

Question 6

D: Infant mortality `rate’

Answer 6

Infant mortality `rate’ represents the probability of dying before the first birthday.

The infant mortality rates in most western countries is less than 1 per 1000 live births, whereas in low income countries the infant mortality rates are greater than 100 per 1000 live births.

Question 7

D: Child (or under 5) mortality `rate’

Answer 7

Child (or under 5) mortality `rate’ represents the probability of dying before age 5.

Question 8

D: Adult mortality `rate’

Answer 8

Adult mortality `rate’ is usually defined as the probability of dying between the ages of 15 and 60 years.

Adult mortality varies substantially across countries and over time.

Question 9

is age standardisation important in demography?

Answer 9

very

example coming

Question 10

what are Person years

Answer 10

measurement take into account both the number of people in the study and the amount of time each person spends in the study.

For example, a study that followed 1000 people for 1 year would contain 1000 person years of data

Question 11

rate vs risk?

Answer 11

Rate - frequency by which events occur (in person-time) - e.g. births

Risk - probability of a specified event within a specified period - e.g. stroke risk

Question 12

3 measures of fertility?

Answer 12

1. Total fertility rate – total births in the average reproductive lifetime
2. Gross reproductive rate - are mother’s reproducing themselves?
3. Net reproductive rate - are mother’s being maintained?

Question 13

does crude mortality rate tell you if a person is healthy or unhealthy?

Answer 13

no

Question 14

Sex ratio at birth commonly assumed to be …

Answer 14

Sex ratio at birth commonly assumed to be 105 males : 100 females

Question 15

describe why age standardisation is important?

how many methods are there?

Answer 15

Ie. Retirement town vs university town

• This allows us to specify the relative weight of the contribution of each age stratum to the summary rate
• It requires sufficient deaths in each age-stratum to produce stable age-specific rates

2 methods

= age standardized rates, or life expectancy

Question 16

describe the direct method of age standardisation

Answer 16

The ‘direct method’ projects the age-specific death rate of the population of interest onto a ‘standard population’ and calculating the overall death rate for that standard.

i.e. expected / observed

NB. The standard population must contain the population of interest (such as projecting the population of Cambridge onto that of the whole UK)

Question 17

describe age standardisation - indirect method?

Answer 17

‘Indirect method’ - looking at population of interest through use of national average

i.e. observed / expected

Question 18

gaps:

Answer 18

Question 19

T or F

Life tables are usually constructed for men and women separately

Answer 19

T

Question 20

why are life table projections are not truly representative?

Answer 20

since they are based on estimated age-specific mortality rates in the recent past, the projections are not truly representative, especially due to current advances in medicine, public health and safety standards which did not exist in the early years of the cohort.

Question 21

are life expectancy values dependant on age structure

Answer 21

independant

Question 22

when are life expectancy values calculated at?

Answer 22

birth

Question 23

do many people outlive their life expectancies?

Answer 23

yes - due to medical advancement.

Question 24

Answer 24

Question 25

Is life Expectancy usually done for men and women differently?

Answer 25

yes

Question 26

T or F ## Footnote The increasing proportion of elderly population in western countries is decreasing the apparent birth rate

Answer 26

T

Question 27

list the 7 big health transitions that caused life expectancy to rise, adn mortality to fall

Answer 27

Question 28

when were the biggst gains made in the reductionof child mortality? and adult mortality?

Answer 28

child mortality: early 20th century adult mortality: late 20th century

Question 29

did child (\<5) mortality plumet around 1900? why?

Answer 29

yess. conquored in the home lost of baby care, cleaness advice campagines to cahnge parental behaviour

Question 30

what leads to the main gains for adult drop in mortality in late C20?

Answer 30

Streptomycin for TB and the drop in tobbaco related

Question 31

Multiplegenomealignment for comparing genomes?

Answer 31

Question 32

what is a Principal component analysis

Answer 32

a 2D representation of the distribution of polymorphisms used for entire populations too

Question 33

Principal component analysis big picture

Answer 33

Question 34

Penetrance vs. expressivity

Answer 34

'**Penetrance**' - % of individuals with a given genotype who exhibit the phenotype - complete vs. incomplete ‘**Expressivity**' - variation in phenotype when the genotype is present

Question 35

What are the processes underlying genome evolution?

Answer 35

Beneficial alleles (increasing fitness) are favoured; deleterious alleles (decreasing fitness) disfavoured. poor card + Natural selection Germline mutation fgenetic Drift Founder effect

Question 36

D: natural selection

Answer 36

Natural selection - choosing between existing alleles - positive, negative, balancing

Question 37

D: Germline mutation

Answer 37

Germline mutation - introducing new alleles

Question 38

D: Genetic drift?

Answer 38

Genetic drift - transition in allele frequency between generations - mapped by the Wright-Fisher model

Question 39

D: Founder effect and population bottlenecksneity’

Answer 39

Founder effect and population bottlenecks - ‘causing non-representative heterogeneity’

Question 40

genetic drift is larger in \_\_\_\_\_populations

Answer 40

smaller populations -

Question 41

smaller or larger populations show higher loss of Genetic diversity

Answer 41

Smaller

Question 42

D: chi squared test

Answer 42

The Chi-squared test is a statistical method used to determine the likelihood that differences in data sets are due to chance. - Small p values mean the likelihood it is due to chance is very low - We can use this test in GWAS studies when determining the likelihood that an allele has on the development of a particular polygenic condition Most traits, including common diseases, are highly polygenic. They depend on many loci (1000s) genome-wide, each contributing only a very small effect.

Question 43

what are GWAS

Answer 43

GWAS Studies Calculate association tests at loci across the genome – for polygenic conditions Low P-values correspond to loci associated with the disease in question

Question 44

fat

Answer 44

mamba