Complete question:
Hemophilia is an X-linked recessive disorder (Xh) that is passed through generations and can be traced by using a pedigree.
Based on the pedigree that is shown, which describes John?
- expresses hemophilia and died of complications
In the attached files you will find the pedigree used to answer this question.
Answer:
John does not have hemophilia.
Step-by-step explanation:
A pedigree is a tree representation of the family history. There are certain symbols that can be globally used to recognize the genotypes and phenotypes of each individual in each generation of the family. By interpreting these symbols we can understand the inheritance pattern of different traits or diseases in families.
Among other symbols, we might recognize the followings,
Basic symbols:
Symbols color:
- Black or full-colored symbol: Affected individual, or individual with the trait under interest
- White symbol: Normal individual
Lines:
- Horizontal lines: Express relationships between individuals
- Vertical lines: Express descendants
- Double line: Consanguinity
According to this information, and the given pedigree, we can see that John is represented by a white square. We know that hemophilia is an X-linked recessive disorder (Xh), so assuming that XH is the gamete with the normal dominant allele, then John must have the genotype XHY.