Question

In humans, a rare dominant disorder known as nail-patella syn- drome causes abnormalities in the fingernails, toenails, and knee caps. Researchers have examined family pedigrees with regard to this disorder and, within the same pedigree, also examined the individuals with regard to their blood types. (A description of blood genotypes is found in Chapter 5.) In the pedigree below IAIA Pi Il IAİ İAİB IAIB IAİ İAİ İBİ

Does this pedigree suggest any linkage between the gene that causes nail- patella syndrome and the gene that causes blood type?

Please explain fully to include phenotype, genotype, type of inheritance, and anything else that well assist in the understanding of this pedigree.

I get that the IBi gene is linked blood type to nail-patella disorder, but how do I understand that from the material presented.

Thank you for assistance in understanding this material.

Answer 1

Yes there is strong linkage between genes for nail patella syndrome and those for blood groups ABO due to being located on same loci of 9th chromosome . There is no crossing over between two genes . Where ever dominant blood group alleles are present in pedigree chart like A, B we se trait of diseaes is there . Trait is autosomal dominant where presence of only single allele sufficient to bring the effect .