Based on previous family studies, an autosomal recessive disease with alleles A and a is suspected to be linked to an RFLP marker. The RFLP marker has four alleles, R₁, R₂, R₃, and R₄. The accompanying pedigree shows a three-generation family in which the disease is present. The gel shows the RFLP alleles for each family member directly below the pedigree symbol for that person. After determining the genotypes for the RFLP and disease gene for each family member, answer the following questions.

Based on your analysis, what is the recombination frequency in this family? Explain how you obtained your answer.

For six genes known to be linked on chromosome 10 of corn (Zea mays), the recombination frequencies between various pairs have been determined in a series of genetic crosses. Use the recombination frequency data in the table below to determine the order of and distance between the genes on a genetic map. The gene lc1 is known to be closest to the telomere of the chromosome.

Based on previous family studies, an autosomal recessive disease with alleles A and a is suspected to be linked to an RFLP marker. The RFLP marker has four alleles, R₁, R₂, R₃, and R₄. The accompanying pedigree shows a three-generation family in which the disease is present. The gel shows the RFLP alleles for each family member directly below the pedigree symbol for that person. After determining the genotypes for the RFLP and disease gene for each family member, answer the following questions.

Is there any evidence of recombination in this pedigree? If so, identify the recombinant individuals and illustrate the recombination that has occurred.

Based on previous family studies, an autosomal recessive disease with alleles A and a is suspected to be linked to an RFLP marker. The RFLP marker has four alleles, R₁, R₂, R₃, and R₄. The accompanying pedigree shows a three-generation family in which the disease is present. The gel shows the RFLP alleles for each family member directly below the pedigree symbol for that person. After determining the genotypes for the RFLP and disease gene for each family member, answer the following questions.

What is the most likely arrangement of syntenic alleles for the RFLP and the disease gene in I-1 and I-2?

The accompanying pedigree below shows a family in which an autosomal recessive disorder is present. Family members I-2 and II-2 are affected by the disorder and have the genotype dd. A pregnancy involving II-4 has just undergone genetic testing for a VNTR that is linked to the disease gene. The VNTR has a recombination frequency of r = 20 with the disease gene. The VNTR has two alleles, V₁ and V₂. The gel electrophoresis patterns for each family member are shown, including the VNTR genotype for II-4. Based on the information given, answer the following questions about the family.

What is the chance II-4 has the disease?

Divide a clean sheet of paper into four quadrants and draw one pair of homologous chromosomes in each quadrant. Draw the chromosomes with two sister chromatids each. The four sets of homologous pairs are identical. Label one chromosome of each pair with alleles A₁ and A₂ and the other member of each pair with the alleles A₁ and A₂. You are to illustrate a single crossover between the homologs in each quadrant and list the parental and recombinant chromosomes, but you are to illustrate four different ways the crossover can occur by involving different chromatids in each illustration.