Question

 

1 Explain gene flow?  Does gene flow lead to adaptive evolution?

2 Explain genetic drift / how does gene pool affect in small populations and preservation of rare species ?  

3 In what way can founder effect lead to genetic drift in a population?

4 Explain founder effect how gene pool change ?

5 Explain directional, disruptive and stabilizing of natural selection

6 What is a balanced polymorphism? and explain the heterozygote advantage in terms of sickle cell anemia.

Answer 1

 

1. In population genetics, gene flow is that the transfer of genetic variation from one population to a different. In some cases migration may end in the addition of novel cistrontic variants to the gene pool of a species or population.Natural selection solely acts on the population's heritable traits: choosing for useful alleles and therefore increasing their frequency within the population, whereas choosing against deleterious alleles and thereby decreasing their frequency—a method referred to as adaptive evolution. gene flow helps keep alleles in a population homogenized whereas natural selection will increase genetic variation and always moves toward creating new species therefore gene flow may facilitate adaptive evolution.

2. Genetic drift may be a change within the frequency of an allele inside a population over time. this transformation within the frequency of the gene or factor variation should occur randomly in order for genetic drift to occur.

Typically, genetic drift occurs in s, small population wherever infrequently-occurring alleles face a bigger probability of being lost. Genetic drift may end up in the loss of rare alleles and may decrease the size of the gene pool. smaller populations have less variation and, therefore, a lower ability to respond favorably — that's, adapt to ever-changing conditions.

3. Genetic drift will cause huge losses of genetic variation for small populations.. A founder effect happens once a new colony is started by a few members of the initial population. This small population size implies that the colony could have: reduced genetic variation from the initial population. Alleles that were present but comparatively rare within the original population will move to 1 of 2 extremes.

4. In population genetic science, the founder effect is that the loss of genetic variation that happens once a new population is established by a really small number of individuals from a bigger population.

Genetic drift can cause massive losses of genetic variation for small populations. Population bottlenecks occur once a population's size is reduced for at least one generation. ... A founder effect happens once a new colony is started by a couple of members of the initial population

5. Natural selection will turn out 3 completely different effects on the genetic variation of a population. These 3 modes, called directional, stabilizing, and disruptive selection,

. In directional selection, a population's genetic variance shifts toward a new phenotype when exposed to environmental changes. stabilizing selection leads to a decrease of a population 's genetic variance once natural selection favors an average phenotype and selects against extreme variations. Disruptive selection may be a kind of natural selection that selects against the average individual in a population. The makeup of this kind of population would show phenotypes (individuals with groups of traits) of each extreme however have only a few individuals in the middle

6. Balanced polymorphism could be a situation during which 2 completely different versions of a gene are maintained in a population of organisms because individuals carrying each versions are better able to survive than those that have 2 copies of either version alone. ... completely different versions of a gene are known as alleles.

in heterozygote advantage, then carriers of the disease (people who are heterozygous, with one normal factor and one for the illness) will be additional likely to survive than people without the disease allele. Since the allele helps survival, it'll spread throughout the population. This looks to be why some genetic diseases are quite common.
A well-established case of heterozygote advantage is that of the gene involved in sickle cell anaemia. there's a strong heterozygote advantage: people with one copy of the allele (we say they need the sickle cell trait) are resistant to the sickness malaria. ... It causes disease by burrowing into red blood cells. however in people with sickle cell trait, the red blood cells are resistant to malaria infection.