Question

which of the following individuals will show a dominant phenotype?
hh only
yy only
gg only
a&b
a&c
question 7
having albinism is a recessive disease, where a = normal pigment and a = albino. mary is albino. what is her genotype?
aa
aa
aa
aa or aa (need more information to answer with certainty)
question 8
albinism is a recessive disease. jack is not albino, but he is adopted. what is his genotype?
aa
aa
aa
aa or aa (need more information to answer with certainty)

Explanation:

Question 7 (Dominant Phenotype)

To determine which individuals show a dominant phenotype, we recall that a dominant phenotype is expressed when at least one dominant allele is present (e.g., for a gene with alleles \( H/h \), \( Y/y \), \( G/g \), dominant alleles are \( H \), \( Y \), \( G \); recessive are \( h \), \( y \), \( g \)).

• \( Hh \): Has dominant allele \( H \) → dominant phenotype.
• \( YY \): Has dominant allele \( Y \) (homozygous dominant) → dominant phenotype.
• \( gg \): Homozygous recessive → recessive phenotype.
• \( a\&b \) would include \( Hh \) (a) and \( YY \) (b), but let's check options: Wait, the options are: Hh only, YY only, gg only, a&b, a&c. Wait, likely the dominant alleles: for a dominant phenotype, genotypes with at least one dominant allele. So \( Hh \) (has \( H \)), \( YY \) (has \( Y \)), and if there's another (like maybe \( A \) dominant), but from the options, the correct one is the combination of those with dominant alleles. Wait, maybe the options are about different genes: assume \( H \) dominant, \( Y \) dominant, \( G \) dominant. So \( Hh \) (dominant), \( YY \) (dominant), \( gg \) (recessive). So the option with both \( Hh \) and \( YY \) (a&b? Wait, original options: "Hh only", "YY only", "gg only", "a&b", "a&c". Wait, maybe "a" is Hh, "b" is YY, "c" is something else. So individuals with dominant phenotype are those with at least one dominant allele: \( Hh \) (has \( H \)) and \( YY \) (has \( Y \)), so "a&b" (if a=Hh, b=YY) would be correct. But maybe I misread. Wait, the question is "Which of the following individuals will show a dominant PHENOTYPE?" So dominant phenotype is expressed when the genotype has at least one dominant allele (for autosomal dominant, or dominant allele in general). So \( Hh \): dominant (since \( H \) is dominant), \( YY \): dominant (homozygous dominant), \( gg \): recessive. So the correct option is the one that includes the dominant ones. If "a&b" means Hh (a) and YY (b), then that's correct. But let's proceed.

Albinism is recessive, so the allele for albinism (\( a \)) is recessive, and normal pigment (\( A \)) is dominant. For a recessive disorder, an individual expresses the disorder (is albino) only if they have two recessive alleles (\( aa \)), because the dominant allele (\( A \)) would mask the recessive one. Mary is albino, so her genotype must be \( aa \) (homozygous recessive) to express the recessive trait.

Albinism is recessive (\( a \) = albino, \( A \) = normal). Jack is not albino, so his phenotype is normal. A normal phenotype can result from two genotypes: \( AA \) (homozygous dominant) or \( Aa \) (heterozygous, since \( A \) is dominant and masks \( a \)). Without knowing his parents’ genotypes (to determine if he could be a carrier), we cannot be certain if he is \( AA \) or \( Aa \). Thus, his genotype is \( AA \) or \( Aa \) (need more information to answer with certainty).

Answer:

(Assuming "a" is Hh, "b" is YY, "c" is another recessive) The correct option is the one with individuals having dominant alleles, so likely the option with \( Hh \) and \( YY \), e.g., a&b (depending on option labels, but the key is dominant phenotype requires at least one dominant allele).

Question 7 (Revised, assuming standard dominant/recessive):

For a dominant phenotype, the genotype must have at least one dominant allele (e.g., \( H \), \( Y \), \( G \) are dominant; \( h \), \( y \), \( g \) are recessive).

• \( Hh \): Has dominant allele \( H \) → dominant phenotype.
• \( YY \): Homozygous dominant (has \( Y \)) → dominant phenotype.
• \( gg \): Homozygous recessive → recessive phenotype.

If options are:

• Hh only
• YY only
• gg only
• a&b (a=Hh, b=YY)
• a&c

Then the individuals with dominant phenotypes are \( Hh \) (a) and \( YY \) (b), so the answer is a&b.

Question 8 (Mary’s Genotype - Albinism)