genetic variation Flashcards

1
Q

population

A

group of organisms of the same species which live in a particular geographical area and have the
capability of interbreeding.

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2
Q

Population genetics

A

study of patterns and causes of genetic variation

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3
Q

Biological variation

A

phenotypic intra-species differences have a genetic basis (DNA) and may
have influence from the environment. Not only humans experience intra-species variation.

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4
Q

Genetic variation

A

catalyst for evolution. The source of variation is mutation which is a change in the DNA,
producing an altered gene (allele).

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5
Q

Genome wide association studies

A

sample genetic variations across a cohort of people who have the disease and a control cohort.

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6
Q

different forms of mutations

A
  • sequence polymorphism
  • length polymorphism
  • copy number variation
  • chromsome inversion
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7
Q

Evolution is a 2-step process

A

Step 1: You must create variation through mutations.

Step 2: Evolutionary forces then change allele frequencies over time.

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8
Q

what are the different types of evolutionary forces

A
  • mutations
  • gene flow
  • random genetic drift
  • natural selection
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9
Q

mutation

A

produces variation by continually producing new alleles.

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10
Q

Gene Flow

A

If one population that has one particular allele and interacts with another population, over time you will have a mixture of the two types of alleles in this population.

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11
Q

random genetic drift

A

It samples variation. Allele frequencies change due to chance.
- Typically during random genetic drift, an allele can be lost or fixed by chance.

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12
Q

Founder effect

A

a small group from an original population migrates and start their own founder
population increasing the allele frequency in that population which reduces genetic diversity

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13
Q

Bottleneck

A

a population is wiped out whereafter a selective pressure is advantageous to only some genotypes (fitness advantage) changing allele frequencies which reduces genetic diversity.

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14
Q

Natural selection

A

where some genotypes in a population leave more offspring than others.

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15
Q

Hardy-Weinberg law:

A

absence of evolutionary forces results in allele frequencies remaining constant from
generation to generation.

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16
Q

Assortative mating

A

form of sexual selection in which individuals with similar genotypes and/or phenotypes
mate with one another more frequently than would be expected under a random mating pattern.

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17
Q

Negative assortative mating

A

you pick a mate that is different to you resulting in an excess of heterozygotes.

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18
Q

Positive assortative mating

A

you pick a mate this is similar to yourself resulting in a deficiency of heterozygotes.

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19
Q

Inbreeding

A

Mating of consanguineous individuals increases the frequency of homozygotes in a population and decreases heterozygote frequency

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20
Q

Deleterious biological consequences

A

Consanguineous unions can increase the frequency of offspring with rare deleterious recessive conditions
- inbreeding depression

21
Q

Coefficient of inbreeding

A

probability that an individual has 2 genes at a locus that are identical by descent

22
Q

HETEROZYGOTE ADVANTAGE

A

you are likely to present more parts of a virus to your immune system than if you are homozygote for particular HLA alleles.

23
Q

polygenic model of inheritance

A

The model suggests how multiple genotypes can influence a particular phenotype

24
Q

hertiability

A

proportion of phenotypic variation attributable to genetic variation in a population.

25
measuring heritability
The coefficient of relationships is represented by ‘r’ for two individuals in the proportion of genes that are identical by descent (recent copies
26
Concordance rates
refers to when both members have a condition. | - It is tested within monozygotic twins and dizygotic twins.
27
Continuous traits
show a series of overlapping phenotypic classes (eg. height and weight
28
discontinous traits
traits show distinct phenotypes (eg. cancer and schizophrenia).
29
hertiability complications?
- hertiability is not constant - assortaive mating - genotype environment interaction - modification of histones
30
USES OF HERITABILITY
- predicting offspring value | - response selection
31
linkage vs association studies
- Linkage studies: seeks to identify chromosomal segments shared by affected family members. Affected sibling pairs results in large sample sizes. - Association studies: measures preferential segregation of a particular allele with a phenotype across families (eg. case control studies) usually in smaller sample sizes
32
Behaviour
interface of the organism with its environment and as such preceded the evolution of many anatomical and physiological features. Behaviour is part of our interactions with one another.
33
Survival:
recognising and avoiding predators and parasites; efficient foraging (obtaining energy); cooperating and competing with conspecifics.
34
Reproduction:
recognising and accessing mates; appropriate levels of care of offspring, infantilism, neglect.
35
sexual selection
Increased individual fitness through obtaining a larger number of mates or better quality mates.
36
Altruistic behaviour
behaviour that conveys an individual fitness cost to the actor and a fitness benefit to the recipient that may improve chances of reproductive success (helping an individual for no reason with no benefit).
37
Kin selection:
if the solution exceeds the constraint then a behaviour with an individual fitness cost can evolve.
38
Individual learning
allows individuals to respond to the environment he or she experience. • Experience can change or reinforce behaviour.
39
Social learning
allows individuals to respond without the potential cost of individual learning
40
Ecology
relationship of an organism to its environment. It is the study of factors determining the numbers and distributions of an organism.
41
Human ecology
the inter-relationships between humans and their environment (selective pressures). • The environment provides selective pressure in order to reproduce more efficiently than their competitors.
42
Adaptation:
sum of ecological interactions; process of interaction between the environment and a population.
43
Types of genetic adaptations
- species wide - population specific - acclimatisation - acclimation
44
1st law of thermodynamics
energy cannot be created or destroyed, only converted from one form to another.
45
2nd law of thermodynamics
energy conversions result in loss of free energy in the system (increased entropy
46
Leibig’s law of the minimum
distribution of a species is controlled by that environmental factor for which the organism has the lowest range of adaptability or control
47
Law of tolerance
distribution determines by upper and lower bounds of physical tolerance.
48
human disease how it effects populations
Disease: old adaptation in new environment. • Natural selection does not set out to enhance health but maximises our number of offspring. • Natural selection has much less power in later life than in early life (low reproductive value).