Question

The fitness of the A1A1, A1A2, and A2A2 genotypes are 1.2, 0.9, and 1.0, respectively. Calculate the selection coefficient and heterozygous effect. What kind of selection is this? Where will the population ultimately end up in terms of allele frequencies?

Answer 1

The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, the brainstem and the cerebellum. It controls most of the activities of the body, processing, integrating, and coordinating the information it receives from the sense organs, and making decisions as to the instructions sent to the rest of the body. The brain is contained in, and protected by, the skull bones of the head. The cerebrum is the largest part of the human brain. It is divided into two cerebral hemispheres. The cerebral cortex is an outer layer of grey matter, covering the core of white matter. The cortex is split into the neocortex and the much smaller allocortex. The neocortex is made up of six neuronal layers, while the allocortex has three or four. Each hemisphere is conventionally divided into four lobes – the frontal, temporal, parietal, and occipital lobes. The frontal lobe is associated with executive functions including self-control, planning, reasoning, and abstract thought, while the occipital lobe is dedicated to vision. Within each lobe, cortical areas are associated with specific functions, such as the sensory, motor and association regions. Although the left and right hemispheres are broadly similar in shape and function, some functions are

Answer 2

As the fitness of the genotypes are better in two homozygous alleles A1A1 and A2A2 than the heterozygous one A1A2. It can be said that the selection favours the two extreme species while the middle heterozygous fitness of the genotypes decreases.

This could mean that the selection type is diversifying selection, here the population tends to move to any extreme(not necessarily any one, population is distributed among two homozygous genotypes) rather than staying in the middle stable portion of a population curve(like stabilizing selection).