Explain why familial breast cancer shows a dominant pattern of inheritance in a pedigree even though it is recessive at the cellular level. Homozygous normalHeterozygous for BRCA-1 mutation, unaffectedNormal cellCancer cellHeterozygous for BRCA-1 mutation, affectedBE A-1-BEA-TBEA-1-BRCA-1(Inheritedmutation)(Occursin a(Inheritedmutation)somaticcell)Heterozygote-cellhas one functionalcopy of BRCA-1Loss of heterozygosity-cell has zero functionalcopies of BRCA-1(a) Pedigree for familial breast cancer(b) Development of cancer at the cellular levelFIGURE 25.18 Inheritance pattern of familial breast cancer. (a) A family pedigree that involves a loss-of-function mutation in the BRCA-1gene. The individuals in this pedigree were tested to determine if they carry a mutation in the BRCA-1 gene. Affected individuals are shown with blacksymbols. The disorder follows a dominant pattern of inheritance. (Note: Males can occasionally develop breast cancer, although it is much more commonin females.) (b) Breast cancer at the cellular level. Normal cells in an affected individual are heterozygous, where as cancer cells in the same individualhave lost their heterozygosity. Therefore, at the cellular level, cancer is recessive because both alleles must be inactivated for it to occur.

Name: Explain why familial breast cancer shows a dominant pattern of inherit
Uploaded: 2024-03-20T06:42:55.000Z
Channel: Bartleby
Description: Explain why familial breast cancer shows a dominant pattern of inheritance in a pedigree even though it is recessive at the cellular level. Homozygous normalHeterozygous for BRCA-1 mutation, unaffectedNormal cellCancer cellHeterozygous for BRCA-1 mut