A pedigree shows late-onset disease with RFLP linkage. Which grandchildren are affected?
In pedigree analysis of late-onset autosomal disorders, linked RFLP alleles cosegregate with the disease mutation due to physical proximity on the chromosome, reducing recombination. Affected parents transmit the disease-associated restriction fragment to progeny. Grandchildren inheriting that specific fragment exhibit the disease phenotype, while those receiving alternative fragment remain unaffected. Recombination between marker and disease locus could break association, but tightly linked markers show minimal recombinant proportion. This principle enables predictive testing and tracking of
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.