Answer:
Changes in gene expression
Explanation:
This phenomenon is the result of changes in gene expression. That means, how the information in the DNA is used by the cell. The genes that are active in the cells of the brain will be very different from the genes that are active in the cells of the bone marrow.
These patterns of gene expression are different for each cell, and dictate the identity of that cell. Gene expression patterns are controlled by a variety of factors in the cell that allow tissue-specific expression, such a transcription factors.
This can also be facilitated by another layer of regulation called epigenetics, which literally means "on top of" genetics, and refers to modifications of DNA (and the proteins around it), that can reflect and influence the activity of the genes within.
Answer:
Smaller populations have a greater chance of having one allele expressed disproportionately.
Explanation:
Genetic drift corresponds to a drastic casual alteration of the natural order, reaching the genotypic concentration of one or several species, not preliminarily involving natural selection factors, but caused by sudden events. Such phenomenon is characterized by the occurrence of ecological catastrophes, for example: earthquakes, tsunamis, tornadoes, floods, burnings, avalanches and other processes, affecting a large population contingent. Thus limiting the genetic content of a particular group, restricted to the prevailing individuals.
In this situation, with low variability, differentiated individuals will experience a more significant selection pressure in relation to the ascending lineage, which minimized the achievements of selection due to the high number of living individuals. In this scenario, smaller populations will have a greater chance of having a disproportionately expressed allele as the number of members is reduced. We can also see this effect if by using a coin we imagine that heads and tails are two alleles in a population and each coin toss represents one member of that population.
Because of its ability to form large complex and diverse molecules
