A) A textbook definition would be that genetic drift is: a random change in allele frequency caused by a series of chance occurences that cause an allele to become more or less common in a population. In layman's terms, this means that genetic drift happens when luck makes the genetic pool of the population to deviate from what is expected.
B) The cause for this genetic drift is the aformentioned couple. Because amish communities are small and they select partners from their community, having even a couple of carriers of alleles in a community can make the allele freuency much larger than expected; for example, if the community was 100 persons, the percentage would be in the order of 1%, still much larger than the general population. Thus, the cause here is that a small population had a couple of carriers.
C) Sexual reproduction leads to a mixing of alleles from both mother and father and helps diversity. When a population is isolated, the gene pool is fixed and no new genes can come in, reducing diversity. Also some people that have an allele might die, hitting diversity even more. Finally, having a small population creates a strong pressure in some circumstances that leads to elimination of some traits and diversity.
<span>The
answer is allelic frequency. This is also the fraction
of a particular allele of a gene in the population. Allelic
frequency in a population of diploid individuals is calculated using the Hardy Weinberg equation
of p2 + 2pq + q2 = 1. Allelic frequency of all the alleles of the genes must add up to 1 (one).</span>
The answer would be: cell lysis due to the effect of osmotic pressure<span>
Cell membrane is important for microorganism because of it separate things outside cells and inside cells. This way, the cell can keep electrolyte and other useful things like carbohydrate and proteins. The cells also dump toxins and dangerous chemical that it produce outside the membrane so it won't damage organs inside the cells.
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The west Nile Virus is pathogen which caused the West Nile fever and encephalitis. The pathogen was introduced in 1999 in the Western Hemisphere and infected a major population in new york. It then expanded to 12 states and district of columbia. The major carrier of the pathogen was Avian and Mosquitoes species. In between 1999 to 2008, nearly 2500000 people were infected and nearly 1500 people died. Also there were thousands of cases of encephalitis or meningitis.
