Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Genetics > Exam 3: Quantitative Genetics and Complex Disease I > Flashcards

Exam 3: Quantitative Genetics and Complex Disease I Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

quantitative genetics

A

deals with phenotypes that vary continuously (e.g characters such as height or mass) -as opposed to discreetly identifiable phenotypes and gene products (such as bristle number in flies, or presence of a particular biochemical)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

discontinuous (qualitative) traits

A

posses only a few phenotypes (e.g. red or white petals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

continuous (quantitative) traits

A

characteristics vary along a scale of measurement with many overlapping phenotypes (ranges from a low to a high and everything in between)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

GWAS

A

a genome-wide association study is an examination of many common genetic variants in different individuals to see if any variant is associated (co-segregates) with a trait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

DGAT1-2

A

single gene with a big impact; catalyzes the final step of oil synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

polygenic inheritance

A

occurs when one characteristic is controlled by 2 or more genes. often genes are large in quantity but small in effect. (ex height, skin color, and weight) many genes contribute to a phenotypic outcome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

all of the traits Mendel studied were

A

discontinuous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what would have happened if Mendel studied traits with a continuous phenotypes?

A

mendel would not have been able to come to the mathematical conclusions that he did; results would have been difficult to interpret

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

t/f: in the real world, rare that alleles have an equal contribution

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

t/f: if we are trying to understand the genotype of a particular phenotype, each can have a different genotype but still same phenotype

A

true; for a quantitative characteristic, each genotype may produce a range of possible phenotypes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

quantitative characteristics (5)

A
  1. exhibit complex relationships btwn genotype and phenotype
  2. are likely polygenic
  3. may have important environmental influences
  4. phenotypic ranges may overlap
  5. cannot use standard methods to analyze
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

height is a continuous variable and factors that regulate height is

A

very complicated; lots and lots of small contributions from multiple genetic variants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

types of quantitative characteristics (2)

A
  1. meristic characteristics

2. threshold characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

meristic characteristics

A
  • determined by multiple genetic and environmental factors, and can be measured in whole #s
  • animal litter size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

threshold characteristics

A
  • measured by presence or absence

- susceptibility to disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

threshold characteristics display

A

only 2 possible phenotypes (the trait is either present or absent) but they are quantitative bc the underlying susceptibility to the characteristic varies continuously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

when the susceptibility exceeds a threshold value:

A

the characteristic is expressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

susceptibility to disease

A

threshold characteristics (mild response to a disease to having all the symptoms) a certain combination of genes can exceed a threshold and make you senstive to disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

the danger of exceeding a threshold

A

as you accumulate genetic variants, you accumulate genes that make you more susceptible to disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

polygenic inheritance

A
  • refers to quantitative characteristics controlled by cumulative effects of many genes
  • each character still follows Mendel’s rules
  • may be influenced by environmental factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

as the number of loci affecting the trait increases,

A

the number of phenotypic classes increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

distribution (2)

A
  • frequency distribution

- normal distribution: a symmetrical (bell-shaped) curve

23
Q

sample definition

A

a REPRESENTATIVE small collection of individuals from the population

24
Q

population definition

A

a group of individuals of interest

25
Q

what is a population

A

ALL MEMBERS OF A PARTICULAR GROUP (people who live to be 100 yrs old)

26
Q

what is a sample

A

A SUBSET OF THE POPULATION THAT SHOULD BE REPRESENTATIVE OF THE LARGER POPULATION

27
Q

how do we ensure that a sample set is representative of a population?

A

draw at random = truly representative of the population

28
Q

a frequency distribution is a graph that displays

A

the # or proportion of different phenotypes

29
Q

t/f: distributions of phenotypes can assume several different shapes

A

true

30
Q

a distribution with 2 peaks is

A

bimodal (probably reflects some environmental selection as seen in skewed distributions as well)

31
Q

mean

A

average of a set of values

32
Q

variance

A

the variability w/in a group of measurements

33
Q

standard deviation

A

the square root of the variance

34
Q

mean provides information about

A

the center of a distribution.

35
Q

variance provides information about

A

the variability of a group of phenotypes

36
Q

the variance =

A

the standard deviation squared (sd^2)

37
Q

1 SD =

2 SD =

A

1 SD = 66% of the sample

2 SD = 95% of the sample

38
Q

correlation

A

when 2 characteristics are correlated, a change in one characteristic is likely to be associated with a change in the other

39
Q

correlation coefficient (r)

A

a statistical measure of the strength of association

40
Q

what does correlation demonstrate?

A

CORRELATION DOES NOT DEMONSTRATE A CAUSE-AND-EFFECT RELATION. it simply means that a change in a variable is associated with a proportional change in the other variable

41
Q

the correlation coefficient describes the relation btwn

A

2 or more variables

42
Q

a perfect correlation will have a correlation coefficient of

A

1

43
Q

a negative coefficient indicates an

A

inverse relationship

44
Q

the greater the variance, the _

A

more spread out the distribution is about the mean (ex s^2=4.0)

45
Q

small standard error means

A

there is little variance (s^2=0.25)

46
Q

t/f: a correlation coefficient can be computed for a single variable measured for pairs of individuals

A

true

47
Q

regression

A

predicting the value of one variable, if the value of the other is given

48
Q

regression coefficient

A

represents the slope of the regression line, indicating how much one value changes on average per increase in the value of another variable

49
Q

a regression line defines the

A

relation btwn 2 variables; the regression line is the line that best fits all the points on the graph

50
Q

the regression coefficient represents the

A

slope of the regression line

51
Q

the regression coefficient, b, represents the

A

change in y per unit change in x

52
Q

when the regression coefficient is 1, a

A

1-unit increase in x is associated with a 1-unit increase in y

53
Q

when the regression coefficient is 0.2, a

A

1-unit increase in x is associated with a 0.2-unit increase in y

Genetics (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions