0
What else can I help you with?
How is sickle cell alleles maintained through natural selection?
Heterozygous induviduals pass the dominant and recessive alleles to offspring
How is the sickle allele maintained through natural selection?
Heterozygous individuals pass the dominant and recessive alleles to offspring.
How is the sickle cell maintained through natural selection?
Heterozygous individuals pass the dominant and recessive alleles to offspring.
Are new alleles made by natural selection?
No - natural selection does not create new alleles. Variation in alleles needs to exist in the population in order for natural selection to occur. Natural selection will involve the change in allele frequencies over time, but it does not create new alleles. New alleles are the result of mutations.
How do alleles influence natural selection?
It's the other way around: natural selection is the natural process that causes the frequencies of occurence of alleles in the population gene pool to shift.
What effect does natural selection have on the frequency of a recessive lethal allele?
Perhaps not much as the recessive allele is masked in heterozygous condition. Depends on penetration and expresivity of the lethal allele, but any homozygous expression is fatal, so one can expect negative frequency selection; the freqiency is kept low by selection.
How is the sickle cell allele maintained through natural selection?
Individuals with two recessive alleles have very high rates of reproduction.
Why does natural selection act directly on genes?
Selection acts directly on phenotype...expressed traits that decrease an individual's chances of surviving to reproductive age. Many alleles are rare enough that expression is almost nil so the trait remains hidden in the population generation after generation at the same frequency. Domestic descendants of wild rabbits are a panoply of colors, all part of the gene pool where those colors were latent...or quickly eaten. Dominant alleles are directly affected by natural selection only because phenotype and both the homozygous and heterozygous genotypes are the same meaning if they were a non-viable mutation they would potentially be 100 selected against in a very few generations.
What is homozygous recessive genotype?
variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the genetic material for natural selection. Genetic variation is brought about by mutation, which is a permanent change in the chemical structure of a gene. Polyploidy is an example of chromosomal mutation. Polyploidy is a condition wherein organisms have three or more sets of genetic variation (3n or more).
Which is a process that eliments harmful alleles from a gene pool?
natural selection
Are dominant or recessive alleles easier to remove by selection?
Natural selection favors whatever allele provides a selective advantage, so in theory it can operate on either. However, if a recessive allele provides an advantage it will soon shift and become the dominant allele, so it could be argued that natural selection favors dominant alleles. This is only partly true. A dominant gene always has some effect on the characteristics of the organism, even if the owner only has one of them. A recessive gene only affects the characteristics if there is no equivalent dominant gene to mask the effect. If both parents possess the recessive gene there is a chance the offspring will have two of them and this will show in their characteristics. When this happens, natural selection operates on the recessive gene. Much of the time, a recessive gene is present but natural selection does not affect it because there is a dominant gene that masks the effect. If natural selection favours the recessive gene, the dominant gene will quite quickly disappear from the population. This does not make the recessive gene 'dominant' it's just tht there's no longer any competition. If selection favours the dominant gene however, the recessive gene can linger in the population for much longer, because even when it is present, it is not selected against for most of the time. That is why conditions like heamophilia survives for a long time in humans, and you suddenly discover a white deer after many years in a herd of brown deer.
What role do alleles play in natural selection?
Genes are the medium by which inherited traits are passed on to offspring. It is inherited traits, and thus genes, that receive positive or negative selection.
