Mendelian Genetics Review

Front

The genotype AA is an example of

Back

Homozygous dominant

Answer explanation

The genotype AA represents two identical dominant alleles. Therefore, it is classified as homozygous dominant, as both alleles are the same and dominant.

Front

Which kind of trait is ALWAYS seen?

Back

Dominant

Answer explanation

A dominant trait is always expressed in the phenotype when present, overshadowing recessive traits. In contrast, recessive traits only appear when two copies are present, making dominant traits the ones that are always seen.

Front

What is the homozygous recessive genotype for guinea pigs being hairy (H) or hairless (h)?

Back

hh

Answer explanation

The homozygous recessive genotype for guinea pigs is represented by 'hh'. This means both alleles are recessive, resulting in a hairless phenotype. 'HH' is homozygous dominant, and 'Hh' is heterozygous.

Front

Genotype aa is an example of

Back

homozygous recessive

Answer explanation

The genotype 'aa' consists of two identical recessive alleles. This is classified as homozygous recessive, as both alleles are the same and recessive. In contrast, heterozygous would have one dominant and one recessive allele.

Front

Genotype Aa is an example of

Back

heterozygous

Answer explanation

Genotype Aa consists of two different alleles, A (dominant) and a (recessive), making it heterozygous. In contrast, homozygous genotypes have identical alleles, either dominant (AA) or recessive (aa).

Front

Are dominant traits always the most common?

Back

FALSE

Answer explanation

The statement is FALSE because dominant traits are not always the most common. Some dominant traits can be rare, while recessive traits can be more prevalent in a population.

Front

Which trait is dominant in guinea pigs: hairy (H) or hairless (h)?

Back

Hairy

Answer explanation

In guinea pigs, the trait for being hairy (H) is dominant over the hairless trait (h). Therefore, when H is present, the guinea pig will have hair, making hairy the dominant trait.

Front

What is the heterozygous genotype for guinea pigs that can be either hairy (H) or hairless (h)?

Back

Hh

Answer explanation

The heterozygous genotype consists of one dominant allele and one recessive allele. In this case, 'H' represents the hairy trait and 'h' represents the hairless trait. Therefore, 'Hh' is the correct heterozygous genotype.

Front

To see a recessive trait, you need

Back

two lower-case letters

Answer explanation

To express a recessive trait, an organism must have two copies of the recessive allele, represented by two lower-case letters (e.g., 'aa'). One capital letter indicates a dominant trait, while two capital letters indicate homozygous dominance.

Front

A genotype with two different alleles is called

Back

Heterozygous

Answer explanation

A genotype with two different alleles is called heterozygous. In contrast, homozygous refers to having two identical alleles. Dominant and recessive describe the expression of traits, not the genotype itself.