Concept explainers
Gene
a. If
b. If two crossover events occurred between these two genes, what are the genotypes of recombinant chromosomes?
c. Can you make a general statement about how the occurrence of two crossover events between a given pair of linked genes affects the estimate of recombination frequency? (Hint: Think about this problem for a gene pair with a small recombination frequency versus a gene pair with a much higher recombination frequency. See also Figure
Trending nowThis is a popular solution!
Chapter 5 Solutions
Genetic Analysis: An Integrated Approach (2nd Edition)
- What is the expected number of double crossovers based on the map? What is observed number of double crossover’s based on the data in the table? Calculate the interference using the formula.. Interpret the interference in terms of whether a crossover inhibits or stimulates an additional crossover in the same interval of the chromosome?arrow_forwarda. Which progeny are the parental types? How can you tell?b. Which progeny are the recombinants? How can you tell?c. Do the results of this test cross support linkage of the traits? What is the % recombination?arrow_forwardIn the accompanying pedigree, the vertical lines stand for protan color blindness, and the horizontal lines stand for deutan color blindness. These are separate conditions causing different misperceptions of colors; each is determined by a separate gene.a. Does the pedigree show any evidence that the genes are linked? b. If there is linkage, does the pedigree show any evidence of crossing over? Explain your answers to parts a and b with the aid of the diagram. c. Can you calculate a value for the recombination between these genes? Is this recombination by independent assortment or by crossing over?(picture added)arrow_forward
- Please explain your choice: Consider an individual with genotype A/a B/b C/c D/d, descended from one parent with genotype A/A B/B C/C D/D and another parent with genotype a/a b/b c/c d/d. Assume that genes A, B, C, and D are present in this particular order on the same chromosome. What is the minimum number of crossovers that must take place on that chromosome for the individual to generate a gamete with genotype AbCd? (hint: draw homologous chromatids and the crossovers that are taking place between them)arrow_forwardTwo different female Drosophila were isolated, each heterozygous for the autosomally linked genes black body (b), dachs tarsus (d), and curved wings (c). These genes are in the order d–b–c, with b closer to d than to c. Shown in the following table is the genotypic arrangement for each female, along with the various gametes formed by both. Identify which categories are noncrossovers (NCO), single crossovers (SCO), and double crossovers (DCO) in each case. Then, indicate the relative frequency with which each will be produced.arrow_forwardConsider two loci A and B that are 30 cM apart on chromosome 1 in the fruit fly. A paracentric inversion is found to span about half of the distance between these loci, but not include either A or B. What is the approximate recombination frequency expected for these loci in … flies that are heterozygous for this inversion? RF(A-B) for heterozygous flies is … flies that are homozygous for this inversion? RF(A-B) for homozygous flies is …arrow_forward
- Below are the recombination frequencies between pairs of genes A, B, C and D. Based on this, what order do the genes have on a chromosome?arrow_forwardbased on fig 1. Is this karyotype a male or female? Which chromosome is the longest and has the most genes? Which chromosome is the shortest and has the fewest genes? In a normal karyotype, how many autosomal chromosomes are there? identify the disorder in the above karyotype. Why?arrow_forwardIn your own words, explain why a testcross cannot produce more than 50% recombinant offspring. When a testcross does produce 50% recombinant offspring, what does this result mean?arrow_forward
- Hemophilia and color blindness are both recessive conditions caused by genes on the X chromosome. To calculate the recombination frequency between the two genes, you draw a large number of pedigrees that include grandfathers with both hemophilia and color blindness, their daughters (who presumably have one chromosome with two normal alleles and one chromosome with two mutant alleles), and the daughters sons. Analyzing all the pedigrees together shows that 25 grandsons have both color blindness and hemophilia, 24 have neither of the traits, 1 has color blindness only, and 1 has hemophilia only. How many centimorgans (map units) separate the hemophilia locus from the locus for color blindness?arrow_forwardHuman females have two X chromosomes XX; males have one X and one Y chromosome XY. a. With respect to X-linked alleles, how many different types of gametes can a male produce? b. A female homozygous for an X-linked allele can produce how many types of gametes with respect to that allele? c. A female heterozygous for an X-linked allele can produce how many types of gametes with respect to that allele?arrow_forwardGo back to Problem 1, and assume you now study a third gene having alleles C and c. For each genotype listed, what type(s) of gametes can be produced? a. AABBCC b. AaBBcc c. AaBBCc d. AaBbCcarrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning