Question

In humans, Albinism (being an Albino) is a recessive trait. What are ALL of the possible genotypes and

phenotypes of the parents for an offspring to be born albino? (Hint: You may need to draw out different
possible scenarios using Punnett Squares).

Answer 1

Answer:

Both parents exhibit the albino phenotype (aa x aa)
Both parents are carriers and do not exhibit the albino phenotype (Aa x Aa)

Step-by-step explanation:

If Albinism is a recessive trait, it means that an individual must inherit two copies of the albino allele (aa) to exhibit the albino phenotype. An individual with one albino allele and one dominant allele (Aa) will be a carrier of the trait and will not exhibit the albino phenotype.

To determine the possible genotypes and phenotypes of the parents for an offspring to be born albino, we can use a Punnett Square to combine the possible genotypes of each parent. If both parents are carriers of the albino allele, they would each have the genotype Aa. When these genotypes are crossed, the possible outcomes for their offspring would be:

A a
A AA Aa
a Aa aa (albino)

So, the possible genotypes of the offspring would be AA, Aa, or aa. However, only the aa genotype will result in the albino phenotype.

Therefore, the possible genotypes of the parents for an offspring to be born albino are:

Both parents have the aa genotype (aa x aa)
Both parents are carriers of the albino allele (Aa x Aa)
The possible phenotypes of the parents for an offspring to be born albino are:

Both parents exhibit the albino phenotype (aa x aa)
Both parents are carriers and do not exhibit the albino phenotype (Aa x Aa)

Answer 2

To have an albino offspring, both parents must be carriers of the recessive gene for albinism. Therefore, the possible genotypes for the parents are:

AA (not a carrier) x aa (carrier)

aa (carrier) x AA (not a carrier)

Aa (carrier) x Aa (carrier)

Using Punnett squares to determine the possible offspring:

AA x aa: all offspring will be Aa carriers (phenotype: not albino)

aa x AA: all offspring will be Aa carriers (phenotype: not albino)

Aa x Aa: 25% of offspring will be aa (phenotype: albino), 50% will be Aa carriers (phenotype: not albino but carrying the gene), and 25% will be AA (phenotype: not albino)

Therefore, the only scenario where an offspring can be born albino is if both parents are carriers (Aa) and they have a child with the genotype aa.