Question

Huntington's chorea is a genetically linked, debilitating, degenerative disorder with an onset usually after the fourth decade of life. The reason that this disease has not been eliminated through natural selection and is actually quite prevalent among communities in Lake Maracaibo, Venezuela, is that _____.

Answer 1

Huntington's disease persists in populations because individuals can pass on the disease-causing allele before the onset of symptoms, which typically occurs after reproductive age. This late manifestation means the allele remains in the gene pool, despite its detrimental effects.

Step-by-step explanation:

Huntington's chorea, also known as Huntington's disease, is a genetically linked degenerative disorder with symptoms typically emerging after the fourth decade of life. The reason that Huntington's disease has not been eliminated through natural selection, particularly in communities like those around Lake Maracaibo, Venezuela, is because individuals with the disease usually have the opportunity to reproduce before symptoms manifest. Since Huntington's disease is an autosomal dominant disorder, a parent with the disease has a 50% chance of passing the allele to their offspring. The disease's late onset means that individuals who carry the allele can transmit it to the next generation before any signs of the disease appear. Consequently, the diseased allele remains prevalent in the gene pool, allowing the condition to persist across generations.