Genetics: Probability and Alleles

Front

What is the expected genotype ratio of offspring from two heterozygous parents (Aa x Aa) for a dominant trait?

Back

1 AA : 2 Aa : 1 aa

Front

How many chromosomes are in each gamete (sperm or egg) compared to the parent cell after meiosis?

Back

The gametes have half the number of chromosomes as the parent cell.

Front

Which genotype represents a heterozygous organism?

Back

Aa

Front

What is the probability that an offspring from a parent with genotype Aa (heterozygous) and another with genotype aa (homozygous recessive) will have the dominant trait?

Back

50%.

Front

What could be an effect of a mutation in a gene?

Back

The offspring may have a new genetic trait not seen in the parents.

Front

What is a dominant allele?

Back

An allele that expresses its trait even in the presence of a recessive allele.

Front

What is a recessive allele?

Back

An allele that only expresses its trait when two copies are present.

Front

Define homozygous genotype.

Back

A genotype consisting of two identical alleles for a trait (e.g., AA or aa).

Front

Define heterozygous genotype.

Back

A genotype consisting of two different alleles for a trait (e.g., Aa).

Front

What is the purpose of meiosis in sexual reproduction?

Back

To produce gametes with half the number of chromosomes of the parent cell.