Midterm Flashcards
1
Q
A measure of the central tendency of a set of random variables
A
Mean
2
Q
Measures how widely the values of a variable in a set vary
A
Variance
3
Q
Measures how much a set of two variables vary together
A
Covariance
4
Q
It is the expectation of the squared deviation of a variable from its mean
A
Variance
5
Q
It is their average or expected value
A
Mean
6
Q
It is the expectation of the product of the deviations of two variables from their respective means
A
Covariance
7
Q
Measures the degree and direction of the relationship between two variables
A
Correlation
8
Q
Measures the expected change in one variable per unit change in another variable
A
Regression
9
Q
Expected value of a constant =
A
Constant
10
Q
Expected value of a random variable =
A
Sum of all values of random variable/ n
11
Q
What can you do so that the sum of (xi - mean of x) does not equal zero
A
Square the deviation
12
Q
Variance equation
A
= sum (X^2 - 2X(mean X) + (meanX)^2)
13
Q
Sample variance equation V(X)
A
(1/(n-1)) * sum(Xi^2 - 2Xi(meanX) + (meanX)^2)
14
Q
Sample variance V(aX)
A
= a^2V(X)
15
Q
Correlation equation
A
Cov(X,Y)/ (sqrt V(X)*V(Y))
16
Q
Doesn’t matter order
Not causative
Unitless
0 = unrelated
A
Correlation
17
Q
Order matters
Y on X = X is causing Y
Denominator is always variance of the variable that’s causing the other variable (the second variable)
A
Regression
18
Q
Regression equation
A
= Cov(X,Y) / V(X)
19
Q
ANOVA means
A
Analysis of variance
20
Q
Sums of squares equation
A
SST=SSR+SSE
21
Q
SST is the
A
Total sums of squares
22
Q
SSR is the
A
Regression sums of squares
23
Q
SSE is the
A
Error sum of squares
24
Q
Mean Yi is the
A
Mean of observations for the ith individual
25
The proportion of the alleles in a population at a locus that are of a particular type
Allele frequency
26
Proportion of individuals in a population with a particular genotype at a particular locus
Genotyped frequency
27
f(B) = p =
2 * (no. of BB individuals) + 1 * (no. of Bb individuals) / 2 * (total no. individuals)
28
f(b) = q =
2 * (no. of bb individuals) + 1 * (no. of Bb individuals) / 2 * (total no. individuals)
29
q =
1-p
30
f(B) and f(b) are
Allele frequencies
31
f(BB) and f(Bb) and f(bb) are
Genotypic frequencies
32
f(BB) = P =
No. of BB individuals / total no. individuals
33
f(Bb) = H =
No. of Bb individuals / total no. individuals
34
f (bb) = Q =
No. of bb individuals / total no. individuals
35
Even though alleles occur in a ____ state in individuals, they are transmitted ____ from parent to progeny
Paired
Singly
36
How can the allele frequency be the same in sires and dams
If there is random mating and no selection in a large population
OR
If selection occurs at the same rate in males and females
37
Hardy Weinberg equilibrium assumes
Allele frequencies in progeny = those in their parents
38
Used to describe computations
Summation and dot notation
39
Rule 1: sum involving a constant
Ec = c+c+c+c …. +c = nc
40
Rule 2: sum of sequential positive integers
Ej = 1+2+3+ …. +n = n(n+1) / 2
41
Rule 3: sums of the squares of sequential positive integers
Ek^2 = 1^2+2^2+3^2+ …. n^2 = n(n+1) * (2n+1) / 6
42
An equation where any x plugged into an equation will yield exactly one value of y
Function
43
Use a dot to signify a summation over a subscript
Dot notation
44
Dot notation single subscript
Exi = x1+x2+x3+ …. xn = x.
45
What equation does dot notation not work
Exi^2 = x1^2+x2^2+x3^2+ ….. xn^2
46
Dot notation square of sum of xis
(Exi)^2 = (x1+x2+x3+ ….. xn)^2 = (x.)^2
47
Useful to introduce concepts of quantitative variation
Single locus model
48
Inter locus gene action
Different locus
Epistasis
49
Intra locus gene action
Within a locus
Dominance
50
Non-additive gene actions
Dominance
Epistasis
Does not pass parent to offspring
Stick with animal throughout lofetime
51
Our observation of the measurement of a trait
Continuous trait
Phenotypic value (P)
52
Examples of phenotypic value
Milk yield
Fiver diameter
Birth weight
Back fat thickness
53
P =
G+E
54
G is the
Genotypic value
55
E is the
Environmental value
56
Represents the effects of the combination of alleles across loci that an animal inherited
Genotypic value
57
Captures all non-genetic factors that impact the phenotypic value
Environmental value
58
d = 0 means
There is no dominance
Strictly additive gene action
59
d = a or d = -a means
There is complete dominance
60
d>a or d<-a means
There is overdominance
61
d lies between 0 and +a means
Incomplete or partial dominance
62
Mean equation
M = a(p-q) + 2pqd
63
a(p-q) is attributable to
Homozygotes
64
2pqd is attributable to
Heterozygotes
65
The vale of ___ reflects both the mean phenotypic and genotypic value of the population
M
66
Positive mean means that we anticipate
The (blank) rate to be increased on average by _____ if the allele had been introduced into a population at this frequency
67
With no dominance the mean only is a function of the difference in
Allele frequencies
68
If we assume that each loci acts independently (ignore epistaxis) then their joint contribution is simple the
Some of their individual effects
69
Parents only transmit or pass their _____ and not their ______ to their progeny
Alleles
Genotypes
70
The mean deviation from the population mean of individuals that allele from one parent, while the allele received from the other parent came at random from the population
Average effect of an allele
71
Increasing the frequency of allele increases the _____
Mean
Because the average effect of the allele becomes less
72
As the extent or degree of dominance increases, an _____ in the frequency of the allele, f(B), has a _____ impact on the population mean and on its average affect
Increase
Greater
73
The average effect of the allele is simply a function of changes in f(B) and the genotyped value a with
No dominance
74
Re-express the average effect as the difference between the average effects of the pair of alleles
Average effect of an allele substitution
75
What determines the mean genotyping value of their progeny?
The average effects of a parent’s alleles
76
The breeding value of an individual is equal to
Sum of the pair of alleles it carries across all loci
77
The average breeding value of its parents
Expected breeding value
78
The genotyping value can be represented as
G= A+D
79
D means
Dominance deviation
80
A means
Breeding value
81
Mean breeding value and mean dominance deviation value equals
Zero
Because they are expressed as deviations from their respective means
82
Depends on allele frequencies and the additive effect of allele substitution
Variance (additive genetic variance)
83
Depends on allele frequencies and the degree of dominance
Dominance deviation variances
84
Variances are usually maximized at
Intermediary allele frequencies
85
What typically makes up most of the genotypes variance except in the unusual cases of overdominance or extreme allele frequencies
Breeding value
86
IAB is the
Epistatic deviation
87
Multiple loci means our genetic model is
G = A+D+I
88
What are commonly important sources of environmental effects on performance?
Nutritional and climatic factors
89
Environmental effects that remain with an animal throughout its lifetime
Ex. Chronic injuries, diseases, training
Permanent environmental effects
90
Temporary environmental effects examples
Illness that passes
Temporary nutritional deficiency
91
Phenotypic model
P - mean = A+D+I+EP+ET
92
If the phenotypic variance is large, observations lie ______ ___ the mean, and the mean provides ____ information about the population
Farther from
Less
93
V(G) =
V(A) + V(D) + V(I)
94
Correlation between repeated records on an individual
Repeatability
95
Repeatability equation
V(G) + V(EP) / V(P)
96
Heritability broad sense equation
V(G) / V(P)
97
Heritability in narrow sense equation
V(A) / V(P)
98
Indicates that repeated performance records an on animal are very much alike
High repeatability
99
A method for separating total variation between observations into its component parts
ANOVA
100
A measure of the size of the differences of the repeated observations within an individual group
Within-group variation
101
A measure of the size of the differences between groups
Between-group variation
102
The number of independent pieces of information on which the estimate is based
Degrees of freedom
103
The value of repeated records is that they can
Reduce the variance of a mean
Smaller variances = more exact measurements
104
When r>0, repeated records will influence the
Variance of a mean
105
With a high repeatability, repeated measures do _____ to reduce the variance of the mean
Little
106
A low repeatability has a _____ impact on reducing the variance of the mean
Large
107
The percentage of phenotypic difference in the parent observed in the offspring
The proportion of the parents’ superiority or inferiority that is passed onto their offspring
Heritability
108
Can be used for prediction
The regression of adduce or breeding value on phenotype
Heritability
109
Heritability is the _____ limit of repeatability
Lower
