The following pedigree is for BRAC2 mutation on chromosome 1…

The following pedigree is for BRAC2 mutation on chromosome 13. Based on your understanding of inheritance, is it dominant or recessive. What is the probability the III-1 (arrow) inherited the BRAC2 mutation? Note: filled in circles represent known cancer victims with the BRAC2 allele. Does inheriting BRAC2 non-functional allele actually cause cancer? Justify your answer.