Module 5 Review 1042SCG
What is population fragmentation
Reduction in gene flow and changes in gene flow pathways within a structured population
Fst is
Reduction in heterozygosity of a SUBPOPULATION due to nonrandom mating relative to the TOTAL population
Define: Locus
Specific position on a chromosome where a gene is located
Define: Natural selection
Stabilising selection, directional selection, diversifying selection, sexual selection
"H" is the average:
heterozygosity in a population
"A" is the mean number of alleles per ________
locus
What is genetic drift
loss of genetic diversity due to the domination of random processes in small populations
The effective population size is often much ___________ than the actual population size
lower
What is genetic adaptation to captivity
maintaining genetic diversity within captivity
When directly counting alleles is not possible due to the presence of a dominant allele, a different method is to be used. If the gene is X-linked, allele ________________________
may be counted in males
F-statistics can also be thought of as a:
measure of the correlation between genes drawn at different levels of a subdivided population -a measure of genetic diversity within and between subpopulations in a structured population
What is microsatellite genotyping?
microsatellites are tracts of repetitive DNA in which certain DNA motifs are repeated, typically 5-50 times
Change due to a mutation in a single generation is extremely small, therefore the effect on Hardy-Weinberg equilibrium is _____________
negligible
A value of 0.0 indicates
no genetic differentiation- complete random mating
What is a panmictic unit
no group structures or mating restrictions in the population, all individuals are potential partnerts
A gene is polymorphic if the frequency:
of the most common allele is less than a certain percentage (95% or 99%)
A monomorphic gene has only _______ form (allele)
one
The frequency of the AA genotype is
p x p x or p^2
A heterozygote my be produced by an A sperm with an a egg or an a sperm with an A egg. Each of these events occurs with probability ________________ so the total probability of forming an Aa zygote is ________
p x q 2pq
Because L^M and L^N represent 100% of the alleles of this gene, p+q=?
p+q=1
Predicted frequencies of the genotypes in the population are AA(p^2), Aa(2pq), aa(q^2). These predicted frequencies can be obtained by expanding the binomial expression:
p^2 + 2pq + q^2 = 1 ---or (p + q)^2
Each small subpopulation is considered to be ________________________
panmictic unit
"P" is the proportion of:
proportion of genes that are polymorphic
The frequency of the aa genotype is
q x q or q^2
Define: reduce fitness
reduce reproduction and survival rates
What is the Founder Effect?
Describes the loss of allelic variation that accompanies founding of a new population from a very small number of individuals
What are examples of the use of genetics in conservation
Detecting hybridization- rare species are threatened with being 'hybridized out of existence' by crossing with comon species Breeding stock selection- the endangered florida panther suffers from genetic problems due to inbreeding
Define: diploid
contain two copies of a gene
Explain the example of Iberian Lynx
-36 microsatellite markers were used to evaluate the current genetic status of the species and to asses the genetic signatures of its past history -critically endangered due to introduced invasive species, habit fragmentation
What are the three ways in which natural selection can alter frequency distribution of heritable traits
-Stablising selection -directional selection -disruptive selection
What two principles must be present if the population is not evolving
-allele and genotype frequencies do not change across generations -the population is stable
Explain the example of the Northern Hairy-nose Wombat
-conservation biologists have analysed mtDNA and microsatellites to assess genetic variability
What are some importances of genetic factors in conservation
-controversy over the degree of importance that genetic factors contribute to conservation issues -there is now a clear theoretical basis and a growing body of experimental evidence that indicate genetic factors are involved in extinctions
What processes commonly upset Hardy-Weinberg equilibrium
-genetic drift -natural selection -migration either immigration or emigration -mutation
What are the 4 primary concerns of conservation genetics
-genetic factors that affect extinction risk -genetic management regimes to minimize these risks -identification and management of genetic diversity in wild populations -management of genetic diversity in captive populations
What three things are included in conservation genetics?
-genetic management of small population -understanding species' taxonomic uncertainties -molecular markers for forensics
What are the two things that affect ecological genetics in conservation biology?
-important biological/ecological characteristics -forensics: identification
What are are the 6 effects of small populations?
-inbreeding depression -loss of genetic diversity -population fragmentation -genetic drift -genetic load -genetic adaptation to captivity
Explain the example of endangered ethiopian wolf
-it is only found in 6 isolated locations -ethiopian wolf-lower genetic diversity than Gray wolf or Coyote -the observed and expected heterozygosity are similar- random matings within populations
Explain the example of black footed rock wallabies
-limited number of populations on the mainland and on off shore islands -genetic diversity is lower for the Barrow island population -high inbreeding coefficient for Barrow island
What are some assumptions underlying the Hardy-Weinberg principle
-random mating -no mutation -no natural selection -no immigration
What are the two things that affect taxonomic genetics in conservation biology
-resolving taxonomic uncertainties -defining management units
What is inbreeding depression
-the deleterious effects of inbreeding on reproduction and survival- inbreeding can reduce fecundity and survival
What are the theoretical values for Fst
0 to 1
There are three important instances in which the two quantities (N & Ne) can be related directly
1. Variable population number through time 2. Unequal sex ratios 3. Uniform population dispersion
The frequency of the hertozygote genotypes (Aa) is
2pq
The frequency of the L^M allele is:
2x the number of L^ML^M homozygotes plus the number of L^ML^N heterozygotes, all divided by the total number of alleles
The frequency of the L^N allele is:
2x the number of L^NL^N homozygotes plus the number of L^ML^N heterozygotes, all divided by the total number of alleles
If 3 loci are polymorphic and 7 are monomorphic what is P?
3/10=0.3 or 30%
What is the equation for Fst
= (Ht - Hs)/Ht
The evolutionary force of __________________ tends to increase genetic variation within a population but decrease genetic variation between populations, while the evolutionary force of ________________ tends to decrease genetic variation within a population but increase genetic variation among populations. A)migration; genetic drift B)mutation; some types of natural selection C)genetic drift; migration D)some types of natural selection; mutation E)positive assortative mating; negative assortative mating
A
Which of the following evolutionary forces does NOT normally change allele frequencies? A)Random mating B)mutation C)selection D)drift E)migration
A
If the number of alleles at six loci are: 1,2,3,2,1,1 what is A
A= (1+2+3+2+1+1)/6=10/6= 1.67
After genetic drift has continued for a sufficient number of generations, most populations become fixed for one allele or another. That is, genetic diversity within a population decreases. What would A, P, and H be?
A=1 P=0 H=0
_____________________ is the product of sampling errors and change events that may result in changes in allele frequencies A)mutation B)genetic drift C)directional selection D)inbreeding E)Evolution
B
Define: Gene
Basic unit of heredity (physical entity transmitted from parent to offspring during reproduction that influences hereditary traits)
DNA typing is used to compare evidence DNA
C
If there are two alleles, A and a, in a population and the population is at Hardy-Weinburg equilibrium, which frequency would produce the greatest frequency of heterozygotes? A)0.1 B)0.25 C)0.5 D)0.75 E)1
C
Rapid changes in allele frequencies by __________________ take place in populations that are small. A)mutation B)natural selection C)inbreeding D)outbreeding E)genetic drift
E
Suppose that in a population the frequency of a particular recessive condition is 1/400. Assume the presence of only a dominant allele (A) and a recessive (a) in the population and that the population is at Hardy-Weinberg equilibrium. What is the frequency of heterozygotes in the population? A)0.0025 B)0.05 C)0.095 D)0.9025 E)0.0475
C
Define: Genetic Drift
Chance fluctuations in allele frequency which occur in finite populations due to random sampling among gametes
A population that goes through a dramatic reduction in size will experience: A)an effective population size B)Hardy-Weinberg equilibrium C)a genetic rescue D)a genetic bottleneck E)mutation
D
If there is random mating in a population and no evolutionary forces are acting on the population, what will be the expected outcome?A)The allele frequencies will remain the same, but the genotype distribution will change B)The genotype distribution will remain the same, but the allele frequencies will change C)Both the genotype distribution and allele frequencies will change D) Both the genotype distribution and the allele frequencies will remain the same E)No prediction can be made about the genotype distribution and allele frequencies from one generation to the next
D
Supposed that in a population the frequency of a particular recessive condition is 1/400/ Assume the presence of only a dominant allele (A) and a recessive allele (a) in the population and that the population is at Hardy-Weinberg equilibrium. What is the frequency of the recessive allele that causes that condition? A)0.000625 B)0.0025 C)0.025 D)0.05 E)0.95
D
When an allele has a frequency of 1.0 in a population it is ________________ in the population. A)lost B)dominant C)overdominant D)fixed E)recessive
D
_______________________ ultimately produced all new genetic variation in a population. A)outcrossing B)migration C)evolution D)mutation E)equilibrium
D
What are we interested in when investigating the degree of fragmentation in a population
Fst
Hs is the sum of the p's and q's multiplied together x2 Ht is 2pq
Good luck
Proportion of heterozygous individuals at five loci in a population are: 0.00, 0.10, 0.20, 0.05, 0.00. What is H?
H= (0.00+0.10+0.20+0.05+0.00)/5= 0.07
What does the Hardy-Weinburg Principle describe?
It describes a mathematical relationship between allele frequencies and genotype frequencies and allows the prediction of a population's genotype frequencies from its allele frequencies
What is microevolution?
It is the study of the distribution of alleles within population and the mechanism that can cause allele frequencies to change over time
What is the bottleneck effect?
Loss of genetic diversity -a population may have descended from a small number of individuals that have survived in a particular generation
The degress of freedom for a chi-square test of Hardy-Weinburg Equilibrium:
Number of expected genotypes (3)-1=2
A population evolve through changes in it's gene pool, therefore ____________________________ is also the study of evolution
Population genetics
Define: Population
Populations are rarely considered to be one amorphous unit without structure
Which of the following does NOT bring about evolution in a population? A) Small population size B)Migration of individuals from a population with a different genetic structure C)Mutation D)Selection E)Random mating
Random Mating
What is loss of genetic diversity
The ability to evolve in response to change
What is an example of the bottle effect?
The cheetah lack genetic variation due to the climate change which has left only one type of species
Phenotype
The physical expression of the genetic code
What is the formula of how to check % error between the observed and predicted numbers (x^2):
The sum of [(observed-expected)^2]/expected
What is the Balancing selection of natural selection
Unfavorable recessive alleles can persist because they are hidden from selection when in heterozygote individuals -heterozygote advantage is an example of balancing selection
Define: allele
alternative form of a gene
What is allele (haplotype) frequencies
another form of analysis is determining the frequency of the various genetic variants
A value of 1 indicates
complete fixation within the subpopulation for one of the many possible alleles in the system
The range 0.0-0.05 may be:
considered as indicating little genetic differentiation
Define: haploid
contain only one copy
If Hs is not equal to Ht the subpopulation heterogeneity is:
different in each subpopulation and different from the population heterogeneity
What does it mean when the observed and expected genotype frequencies do not seem to be in agreement
excess heterozygotes
Fit is
reduction in heterozygosity of an INDIVIDUAL due to nonrandom mating relative to the TOTAL population
Fis is
reduction in heterozygosity of an INDIVIDUAL due to nonrandom mating within its SUBPOPULATION
Define: allele frequencies
refers to the frequency of an allele
A population after a genetic "bottleneck" may be missing:
some of the alleles present in the previous generations. That is once a population returns to its former size the genetic variation will remain low, often for many generations
What is average heterozygosity
sum of the proportions of heterozygotes at all loci divided by the total number of loci sampled
What is genetic loading- purging
the accumulation and loss of deleterious mutations
Define: Conservation genetics
the application of genetics to preserve species as dynamic entities capable of coping with environmental change
The amount of change in allelic frequency due to migration between populations depends on:
the difference in allelic frequency and the extent of migration
Hs is
the expected heterozygosity of an individual in a random mating
Ht is
the expected heterozygosity of an individual in an equivalent random mating total population
Define: Genotype
the genetic code of an individual
If Hs = Ht the subpopulation heterogeneity is :
the same as the population heterogeneity -random mating throughout the population
The total number of alleles is ________ times the sample size
two times the sample size since each individual is diploid so they contain two copies
