Concept explainers
To review:
The reason due to which the reproductive isolation is partial rather than complete, assuming that the reproductive isolation in phlox is observed because of lethal combinations of incompatible alleles at several loci among the various strains.
Introduction:
In early years, the biologists collected sample of seeds of newly found species of phlox. They distributed these species in nurseries in Europe. These nurseries found more than 200 breeding strains of phlox. These strains differed in flower size, color, and growth of plant. The reproductive isolations were not seen initially but after some subsequent experiments, reproductive isolations were observed.
The incompatibility was seen when the strains were crossed and seed production was measured and compared. The biologists found that reproductive compatibility fell down to 15–60%. This decrease was found due to crossing of the strains, which were isolated.
Want to see the full answer?
Check out a sample textbook solutionChapter 22 Solutions
Life: The Science of Biology
- Which Hardy-Weinberg equation relates the frequencies of the genotypes for a particular gene locus?arrow_forwardNeurospora of genotype a + c are crossed withNeurospora of genotype + b +. (Here, + is shorthandfor the wild-type allele.) The following tetrads areobtained (note that the genotype of the four sporepairs in an ascus are listed, rather than listing alleight spores):a + c a b c + + c + b c a b + a + ca + c a b c a + c a b c a b + a b c+ b + + + + + b + + + + + + c + + ++ b + + + + a b + a + + + + c + b +137 141 26 25 2 3a. In how many cells has meiosis occurred to yieldthese data?b. Give the best genetic map to explain these results.Indicate all relevant genetic distances, both betweengenes and between each gene and the centromere.c. Diagram a meiosis that could give rise to oneof the three tetrads in the class at the far right inthe listarrow_forwardAssume that in a Hardy-Weinberg population, 9% of the individuals are of the homozygous Tecessive phenotyne. What percentage of the individuals would be expected to be heterozygous? What percentage homozygous dominent?arrow_forward
- (a) Assuming that Migaloo’s albinism is caused by a rare recessive gene, what would be the likelihood of the establishment of a natural robust subpopulation of albino white humpback whales in this population? (b) Assuming that Migaloo’s albinism is caused by a rare dominant gene, what would be the likelihood of the establishment of a natural robust subpopulation of albino white humpback whales in this population?arrow_forwarda. Two linked biallelic loci (c = 0.1) have allele frequencies pA = 0.7 and pB = 0.4. If these two sites are in linkage disequilibrium with D = -0.12, what are the expected haplotype frequencies under these conditions? b. What will the linkage disequilibrium parameter D be after 20 generations?arrow_forwardWhat is the segregation ratio of dihybrid? Explain using a Punnett’s square and the generation pedigree.arrow_forward
- Two chromosome inversions are commonly found in populations ofDrosophila pseudoobscura: Standard (ST) and Arrowhead (AR). Whenthe flies are treated with the insecticide DDT, the genotypes for theseinversions exhibit overdominance, with the following fitnesses:Genotype FitnessST/ST 0.47ST/AR 1AR/AR 0.62What will the frequencies of ST and AR be after equilibrium has beenreached?arrow_forwardWhat is the segregation ratio of monohybrid? Explain using a Punnett’s square and the generation pedigree.arrow_forwardWhich of the Pedigree diagrams below is most likely to show a family with Gaucher Disease?arrow_forward
- If two loci R/r and W/w are linked and are 14 map units apart, and an RW/rw individual is testcrossed, you will obtain: Group of answer choices 1)7% RW individuals 2)86% Rw individuals 3)14% RW individuals 4)14% rW individuals 5)43% rw individualsarrow_forwardWhat is the expected genotype frequency of the heterozygous genotype under the Hardy-Weinberg equation P = 0.7?arrow_forwardAssume there is a population with these different percentages of genotypes: 68% BB, 20% Bb, and about 9% bb. Will this be considered in Hardy-Weinberg equilibrium? Why or why not?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning