Lab 10//11: Chromosomal & Genetic Disorders Flashcards

Two parents are carriers of cystic fibrosis.
What are the genotype and phenotype ratios for their children?

Parents: Ff × Ff

Punnett Square:

FF = 25%
Ff = 50%
ff = 25%

Genotype ratio: 1 FF : 2 Ff : 1 ff
Phenotype ratio:

75% unaffected
25% affected (ff)
50% carriers

A carrier father and an unaffected, non-carrier mother have children.
What is the probability their child will:

be a carrier?
have cystic fibrosis?

Parents: Ff × FF

Offspring:

50% Ff (carriers)
50% FF (unaffected)

Chance of CF: 0%
Chance of being a carrier: 50%

A carrier mother and an affected father have a child.
What are the chances their child will:

have sickle cell disease?
be a carrier?

Parents: Ss (carrier) × ss (affected)

Offspring:

50% Ss (carrier)
50% ss (affected)

Chance affected: 50%
Chance carrier: 50%

Two carriers for sickle cell have children.
What are the genotype ratios and phenotype ratios?

Parents: Ss × Ss

Punnett Square:

SS = 25%
Ss = 50%
ss = 25%

Phenotype:

25% normal
50% carriers
25% sickle cell disease

A carrier father and an affected mother have children.
What percent will have PKU?

Parents: Pp × pp

Offspring:

50% Pp (carrier)
50% pp (PKU)

Probability affected: 50%

A carrier mother and a homozygous father have children.
What fraction will be carriers?

Parents: Pp × PP

Offspring:

50% Pp (carriers)
50% PP (normal)

Fraction carriers: 50%

A heterozygous father and a mother with normal digits have a child.
What percentage of their children will have polydactyly?

Parents: Pp × pp

Offspring:

50% Pp (polydactyly)
50% pp (normal)

Probability of polydactyly: 50%

A homozygous dominant mother and a normal father have children.
What percent of their children will have the polydactyly trait?

Parents: PP × pp

Offspring:

100% Pp → 100% polydactyly

A heterozygous father and a normal mother have children.
What are the chances a child will inherit Huntington’s?

Parents: Hh × hh

Offspring:

50% Hh (affected)
50% hh (normal)

Chance of Huntington’s: 50%

Two parents, one heterozygous and one homozygous dominant, reproduce.
What percentage of their children will be affected with Huntington's disease?

Parents: Hh × HH

Offspring:

50% HH (affected)
50% Hh (affected)

100% of children will have Huntington’s

A carrier mother and a normal father have children.
Determine the probability for each:

sons with hemophilia
sons who are carriers
daughters with hemophilia
daughters who are carriers

Parents: XᴴXʰ (carrier) × XᴴY (normal father)

Sons:

50% XʰY → hemophilia
50% XᴴY → normal

Daughters:

50% XᴴXʰ → carriers
50% XᴴXᴴ → normal

An affected male and a normal female have children.
What are the phenotypes of all sons and daughters?

Parents: XʰY (affected male) × XᴴXᴴ (normal female)

Sons:

100% XᴴY → normal

Daughters:

100% XᴴXʰ → carriers

No affected children.

A colorblind father and a carrier mother have children.
What are the chances for:

colorblind sons
colorblind daughters?

Parents: XᶜY (colorblind father) × XᴺXᶜ (carrier mother)

Sons:

50% XᶜY → colorblind
50% XᴺY → normal

Daughters:

50% XᴺXᶜ → carriers
50% XᶜXᶜ → colorblind

A normal father and a carrier mother have children.
What percentage of children will be colorblind?

Parents: XᴺY × XᴺXᶜ

Sons:

50% XᶜY → colorblind
50% XᴺY → normal

Daughters:

50% carriers (XᴺXᶜ)
0% affected

Overall % colorblind children: 25%

A carrier mother and an unaffected father have children.
What percent of sons will have DMD?
What percent of daughters will be carriers?

Parents: XᴰXᵈ (carrier mother) × XᴰY

Sons:

50% XᴰY → normal
50% XᵈY → DMD

Daughters:

50% XᴰXᵈ → carriers
50% XᴰXᴰ → normal

An affected male and a carrier female have children.
What percentage of:

sons will have DMD?
daughters will have DMD?

Parents: XᵈY (affected father) × XᴰXᵈ (carrier mother)

Sons:

50% XᵈY → DMD
50% XᴰY → normal

Daughters:

50% XᴰXᵈ → carriers
50% XᵈXᵈ → affected