Assume that long ear lobes in humans are an autosomal...

Assume that long ear lobes in humans are an autosomal dominant trait that exhibits $30 \%$ penetrance. A person who is heterozygous for long ear lobes mates with a person who is homozygous for normal ear lobes. What is the probability that their first child will have long ear lobes?

Key Concepts

Punnett Square Analysis in Genetic Crosses

Punnett square analysis is a visualization tool used to determine the probability of inheriting particular genotypes and phenotypes from a genetic cross. By mapping the potential gametes from each parent and combining them, one can calculate the likelihood of an offspring inheriting specific allele combinations, which is central to understanding Mendelian patterns of inheritance and associated probabilities.

Genetic Heterozygosity and Homozygosity

Genetic heterozygosity refers to having two different alleles for a given gene, while homozygosity refers to having two identical alleles. In genetic crosses, knowing whether individuals are heterozygous or homozygous for a particular trait helps predict the distribution of genotypes and potential phenotypes among their offspring.

Incomplete Penetrance

Incomplete penetrance is a phenomenon in genetics where not all individuals carrying a dominant allele exhibit the associated phenotype. In such cases, even if the gene responsible for the trait is present, other genetic, environmental, or stochastic factors can prevent its expression. This concept is crucial in understanding why some traits do not appear even when the genetic potential is there.

Autosomal Dominant Inheritance

Autosomal dominant inheritance refers to a pattern where only one copy of a dominant allele is needed for the trait to be expressed. This means that an individual with one copy of the allele will show the trait regardless of the other allele, as long as the dominant allele is present on one of their autosomal chromosomes.

Transcript

Please give Ace some feedback