What characterizes lethal alleles in genetics?

Lethal alleles are characterized by the fact that they can cause death if two copies of the allele are inherited, typically in a homozygous state. This means that certain combinations of alleles can be lethal to the organism, preventing it from developing or surviving past a specific stage, such as during embryonic development.

In many cases, lethal alleles often exhibit a recessive inheritance pattern; for instance, an individual must inherit two copies of the lethal allele (one from each parent) to observe the lethal effect. This can result in specific phenotypic ratios in a population that deviate from the typical Mendelian inheritance expected ratios. Therefore, if a lethal allele is present, individuals who are homozygous for that allele may die before they can reproduce, which affects the frequency of that allele in the population.

This understanding is essential for studying patterns of inheritance and understanding how certain genetic traits can influence survival and population dynamics.