The figure below shows a pedigree of a family in which the autosomal disease allele was transmitted through three generations, along with microarray analysis of each individual for a biallelic SNP locus (the alleles are C and T). a) Is the genetic nature of the disease gene dominant or recessive? Explain. b) If there is genetic linkage between the SNP and the disease locus, which generation will clearly show the existence of this linkage relationship? Explain. c) If genetic linkage exists between a SNP and a disease locus, what can be estimated as the genetic distance between the two loci? d) Suggest a method that can be used to accurately determine the molecular distance between a SNP and a disease locus?
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Individuals III-1 and III-2 are both unaffected but have an affected child (IV-1). This is only possible if the disease allele is recessive. If it were dominant, at least one parent would need to be affected. Show more…
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The figure that follows shows the pedigree of a family in which a completely penetrant, autosomal dominant disease is transmitted through three generations, together with microarray analysis of each individual for a biallelic SNP locus (the alleles are $C$ and $T$ ). a. Do the data suggest the existence of genetic linkage between the SNP locus and the disease locus? If so, what is the estimated genetic distance between the two loci? b. Calculate the maximum Lod score for linkage between the SNP and the disease locus for this pedigree. What does this value of the Lod score signify?
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The figure that follows shows the pedigree of a family in which a completely penetrant autosomal dominant disease is transmitted through three generations. Each member of the family was genotyped at a biallelic SNP locus (the alleles are C and A), and the microarray analysis is presented below the pedigree. Microarray data at SNP a. What matings are informative? (3 pt) b. What is the relative map distance between the disease locus and the SNP? (2 pt) c. Calculate the lod score for this pedigree. Is this enough information to conclude that the disease locus is linked with the SNP locus? (2 pts) d. You analyze a pedigree from a different family with the same disease and SNP alleles and find 12 parentals and 1 recombinant. Calculate the Lod score for this pedigree. Do you now have sufficient data to conclude linkage between the disease and SNP loci? (3 pts)
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