Question

a typical pedigree for a family that carries falconi anemia. note that carriers are not indicated with half-colored shapes in this chart.
recessive pedigree
george
arlene
sandra
tom
sam
ff
wilma
ann
michael
daniel
ff
alan
tina
christopher
f-
carla
ff
analysis questions.
to answer questions #1-5, use the letter \f\ to indicate the recessive falconi anemia allele, and the letter \f\ the normal allele.

1. what is arlenes genotype?
2. what is georges genotype?
3. what are ann & michaels genotypes?
4. most likely, sandras genotype is .
5. list three people from the chart who are most likely carriers of falconi anemia

Explanation:

Step1: Identify affected genotype

Falconi anemia is recessive, so affected individuals have genotype $ff$. Arlene is affected (shaded shape).

Step2: Deduce George's genotype

Arlene ($ff$) and George have an unaffected child Sam ($Ff$). George must pass $F$ to Sam, so George is $Ff$.

Step3: Deduce Ann & Michael's genotypes

Their child Carla is $ff$, so both Ann and Michael must pass $f$. They are unaffected, so their genotype is $Ff$.

Step4: Deduce Sandra's genotype

Sandra and Tom (affected, $ff$) have Daniel ($Ff$). Sandra must pass $F$, so she is $FF$ (most likely, as no indication she is a carrier otherwise).

Step5: Identify likely carriers

Carriers are $Ff$: Sam ($Ff$), Ann ($Ff$), Daniel ($Ff$) (all pass $f$ to offspring or have affected parents/children).

Answer:

1. $ff$
2. $Ff$
3. Ann: $Ff$; Michael: $Ff$
4. $FF$
5. Sam, Ann, Daniel