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
A. the mutated gene is recessive and therefore tough to eliminate from a population.
B. the onset of the disease after prime childbearing years means it is largely unaffected by natural selection.
C. gene flow between the populations around Lake Maracaibo and European settlers maintains the gene in a balanced polymorphism.
D. there has not been enough time since the introduction of the disease for genetic drift to isolate the gene.
Answer: The onset of the disease after prime childbearing years means it is largely unaffected by natural selection.