Let's take a look at some graphs of this to make it a little easier to see. For values of p from 0 to 1, in intervals of 0. All of the above has to do with the allele and genotype frequencies we would expect to see. Next, let's look at the real world situation so we can compare.
In a real world population, we can only see phenotypes, not genotypes or alleles. However, in a population of genotypes AA, Aa and aa, the observed frequency of allele A equals the sum of all of the AA genotype plus half of Aa genotype the A half.
The observed frequency of allele a is therefore half of the Aa individuals the a half plus all of aa individuals. Tip : If the alleles are codominant, each phenotype is distinct you can distinguish between tall, medium and short and your job is easier.
If the alleles are dominant and recessive , we can't visually tell the homozygous AA from the heterozygous Aa genotypes both are tall , so it's best to start with the homozygous recessive short aa individuals. Count up the aa types and you have the observed q 2.
Then, take the square root of q 2 to get q, and then subtract q from 1 to get p. If observed and expected genotype frequencies are significantly different , the population is out of HWE.
Question : Why might observed and expected phenotype frequencies differ? Imagine the following scenarios where natural selection is at work. Situation one favors only one tail of the distribution. Perhaps the tallest, perhaps the shortest, but not both. This is directional selection. Now imagine that both tails of the distribution are selected against, and only the middle is favored.
This is called stabilizing selection. Next imagine that the extremes on both ends are favored. This is called disruptive selection. A average heterozygosity. A Each bird evolved a deeper, stronger beak as the drought persisted. D The frequency of the strong-beak alleles increased in each bird as the drought persisted. A All phenotypic variation is the result of genotypic variation.
B All genetic variation produces phenotypic variation. C All nucleotide variability results in neutral variation. D All new alleles are the result of nucleotide variability. A is created by the direct action of natural selection B arises in response to changes in the environment C must be present in a population before natural selection can act upon the population D tends to be reduced by when diploid organisms produce gametes.
C must be present in a population before natural selection can act upon the population. A using a series of NAs, one at a time, and changed about once a week B using a single PI, but slowly increasing the dosage over the course of a week C using high doses of NA and a PI at the same time for a period not to exceed one day D using moderate doses of NA and two different PIs at the same time for several months.
D using moderate doses of NA and two different PIs at the same time for several months. A There are now fewer genes within the viral particle. B There are now more genes within the viral particle. C A point substitution mutation has occurred in the retroviral genome. D One of the RNA molecules has experienced gene duplication as the result of translocation.
A The longer day lengths of summer trigger the development of twig-like caterpillars. B The cooler temperatures of spring trigger the development of flowerlike caterpillars. D Differences in diet trigger the development of different types of caterpillars.
C Differences in diet trigger the development of different types of caterpillars. A no selection B no genetic drift C no gene flow D no mutation. C no gene flow. Is this population in Hardy-Weinberg equilibrium? A Yes. B No; there are more heterozygotes than expected. C No; there are more homozygotes than expected.
D More information is needed to answer this question. A nucleotide variability B chromosome number C average heterozygosity D nucleotide variability and average heterozygosity. D nucleotide variability and average heterozygosity. A the allele's frequency should not change from one generation to the next B natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency C two alleles are present in equal proportions D individuals within the population are evolving.
A the allele's frequency should not change from one generation to the next. A the population is diploid B heterozygotes can come about in two ways C the population is doubling in number D heterozygotes have two alleles.
B heterozygotes can come about in two ways. D heterozygotes have two alleles. D Allele frequency cannot be determined from this information. A The two phenotypes are about equally adaptive under laboratory conditions. B The genotype AA is lethal. C There has been a high rate of mutation of allele A to allele a.
D There has been sexual selection favoring allele a. A does little to change allele frequencies B is more important in eukaryotes than in prokaryotes C happens in all populations D has no effect on genetic variation. A does little to change allele frequencies. A a genetic bottleneck B sexual selection C habitat differentiation D the founder effect. D the founder effect. D a founder effect.
A natural selection B genetic drift C gene flow D mutation. A natural selection. A population bottleneck and Hardy-Weinberg equilibrium B heterozygote advantage and stabilizing selection C mutation and natural selection D founder effect and genetic drift.
D founder effect and genetic drift. A directional selection B disruptive selection C a founder event D a genetic bottleneck. D a genetic bottleneck. A lower average fitness in both populations B higher average fitness in both populations C increased genetic difference between the two populations D decreased genetic difference between the two populations.
D decreased genetic difference between the two populations. A Mutations caused major changes in rodent physiology over time. B Mutation led to increased genetic variation.
C Mutation caused genetic drift and decreased fitness. D Mutation caused the fixation of new alleles. A nonrandom mating B geographic isolation C genetic drift D gene flow. A cross your flies with flies from another lab B reduce the number of flies that you transfer at each generation C transfer only the largest flies D change the temperature at which you rear the flies.
A cross your flies with flies from another lab. A the limits of historical constraints B the inability to compromise C the consequences of random mutations D the consequences of inbreeding. A the limits of historical constraints. C The strong, thick beak of a woodpecker helps it find insects in trees. Explanation : Hardy-Weinberg equilibrium has a set of conditions that must be met in order for the population to have unchanging gene pool frequencies.
Report an Error. Possible Answers: There is a large population of birds on an island. Birds with black feathers prefer to mate with birds that have similarly colored feathers. Predators do not discriminate between members of the species with different colored feathers. The population is isolated on an island, and new birds are unable to fly to the island. Correct answer: Birds with black feathers prefer to mate with birds that have similarly colored feathers.
Explanation : If a population is in Hardy-Weinberg equilibrium, there is no evolution taking place in the population. Possible Answers: Mutation. Correct answer: Differentiation. Explanation : The Hardy-Weinberg principle is a mathematical model proposing that, under certain conditions, the allele frequencies and genotype frequencies in a sexually reporoducing population will remain constant over generations.
Possible Answers: The population size is large. All of these are assumptions made by Hardy and Weinberg in their equilibrium model. Correct answer: All of these are assumptions made by Hardy and Weinberg in their equilibrium model. Explanation : All of the answer choices are assumptions made when considering Hardy-Weinberg equilibrium.
Possible Answers: genetic drift. Correct answer: genetic drift. Explanation : All the factors listed are factors that can change the genetic equilibrium of a population. Possible Answers: Two populations of island rabbits, separated by 5 miles of ocean. A population of 2,, mosquitos flying over a body of water.
A male bird with large and bright feathers is more fit than other birds. A researcher randomly dividing fruit flies into mating groups. Correct answer: A male bird with large and bright feathers is more fit than other birds.
Explanation : For Hardy-Weinberg equilibrium to be in effect, five conditions must be met: 1. Large Population 2. Isolated populations no immigration or emigration 3.
No spontaneous mutations 4. Mating is random 5. No natural selection. Which of these factors would not contribute to Hardy-Weinberg equilibrium?
Possible Answers: Large population. Correct answer: Natural selection. Explanation : Hardy-Weinberg equilibrium describes no change in genotypic frequencies over multiple generations. If all Hardy-Weinberg conditions are met, what will be the result? Possible Answers: Elimination of homozygote individuals. Constant fluctuation in genotypic frequencies. Correct answer: No change in genotypic frequencies.
Explanation : Hardy-Weinberg equilibrium describes no change in the genotypic frequencies of a population. Copyright Notice.
0コメント