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Is it true that all of the genes in a population make up the allele frequency of the population?
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How is directional selection related to evolution?
Directional evolution is where one allele is selected in a population over another allele. Imagine a certain breed of dog that live in cold weather, they will have genes for thick fur (allele A), they are still caring allele for thin fur (allele a), but its recessive and animals with thin fur often dont make it. So if you looked at a distrubition in a population of these animals you would see a preponderance for A alleles and very low level of a alleles. Now imagine that over time their habitat changed and they no longer need the thick fur, in fact its detrimental to the animal to have thick fur. You would see a allele distribution shift from most animals having genes A to genes a. Even if a is recessive to A, if all the animals with thick fur die out then only those with thin fur can survive.
What does the q represent in hardy-weinberg equation?
It depends on what you make p equal to. P is usually the frequency of the dominant allele, which makes q the frequency of the recessive allele, but they can be switched. As long as p is one frequency and q is the other, the formula will work. So if you have the dominant allele frequency (A) =.6 then the recessive allele frequency (a) =.4, because p+q=1 When you plug the frequencies into the hardy-weinberg equation p^2 +2(p)(q) + (q)^2 = 1 then you have (0.6)^2 + 2(0.4)(0.6) + (0.4)^2 = 1 (0.6)^2 = 0.36 which is the frequency of dominant homozygotes 2(0.4)(0.6)=0.48 which is the frequency of heterozygotes (0.)^2 = 0.16 which is the frequency of recessive homozygotes If you have a population of 100 people, these frequencies would mean that: 36 people would be AA 48 people would be Aa 16 people would be aa Which would mean that 36+48=84 people would exhibit the dominant trait and 16 people would show the recessive trait.
How do you use recessive allele in a sentence?
The building blocks of our genes (that make us what we are) are called alleles and these can be either dominant, recessive or codominant - which means they are equally dominant. Now for your sentence: "A typical example of codominance can be found in blood types, where the existence of A as well as B alleles in a person will lead to blood type AB".
How do you do allele mining for fragrance and colour principles from saffron and sandalowood?
Allele mining is the finding of superior allele from the natural population. As in case of saffron, it required lots of saffron. the main basic concept for allele mining we required a lots of population. But crop like saffron and other clonally propagated crops this technology fails because there is no cross pollination and or self pollination nature. So far development of population is concerned, induced mutation is the way by which we make variability within this crops.
How are alleles different from genes?
A gene is a section of DNA that codes for a specific protein. An allele is the different forms of that gene. The commonly used examples are things such as eye colour (although this is an over simplification as the true nature of the genes governing eye colour are a little more complex): You have a GENE for eye colour. That GENE comes in (normally) two forms. These two forms are called ALLELES. One ALLELE is for blue eyes and one ALLELE is for brown eyes. ALLELES can be DOMINANT, RECESSIVE or CO-DOMINANT.
How can evolution be defined and measured by the frequency of alleles in a gene pool?
It's not gene pools that have a frequency, but allelesthat have a frequency in the gene pool.Alleles are "rival" variants for the same gene. For instance, if hair colour is coded by one gene, then brown hair may be allele A for that gene, while blonde hair is allele B for the same gene.Imagine people as being packages of genes, each containing two full sets of genes (humans are diploid, so we contain two copies of genes in all our cells - but they may be two different alleles for the same gene). Now put the contents of all those people-packages together in one pool: that's your gene pool.The more people have some trait T, coded for by allele A of gene G, the higher the number of copies of allele A will be in the gene pool. That's what's called the allele frequency.
What is the frequency of allele a if allele A has a frequency of 0.9?
The sum of the frequencies of all alleles at a point on a chromosome (the locus) must be 1.0. So, if the frequency of A is 0.9, the frequency of a must be 1.0 - 0.9 = 0.1. If you convert frequencies to percentages (multiply by 100), the total percentage of alleles is 100%. Allele A makes up 90%, so allele a must make up 100 - 90 = 10%.
A population consists of 9 percent white sheep and 91 percent black sheep what is the frequency of the black wool allele if the black wool allele is dominant and the white wool allele is recessive?
If you assume hardy-weinburg equilibrium, then:let B = frequency of black allele (dominant)b = frequency of white allele (recessive)BB (or B^2) = frequency of homozygous black sheep2Bb = frequency of heterozygous black sheepbb (or b^2) = frequency of white sheepSince 9% of the sheep are white, the frequency of white sheep is 0.09, or bb = 0.09, so b=.3, which means B = 1-b = 1-.3 = 0.7You should check to make sure that the hardy-weinburg assumption holds:BB = 0.492Bb = 0.42And BB + 2Bb = 0.91, which is the frequency of black sheep. ?The hardy-weinburg assumption is valid!
What circumstances that genetic drift occur?
Genetic drift is the fluctuation of allele frequencies in a population due to chance. Chance plays a role in several ways. Copies of alleles can be lost because they never make it into gametes. Another possibility is, if the allele copy makes into a sperm, that sperm isn't the one that fertilizes an egg. Maybe the organism that carries copies of the allele in its gametes fails to find a mate, or is killed before reproducing. These kinds of events can influence the frequency of that alelle in a population, and occurs regardless of any selection for or against that allele. Obviously, the smaller the population, the larger the effect drift has on the allele frequency. For example, consider a population of four organisms. Each has two copies of a particular gene (one on each chromosome). Now, consider a mutation that creates a new allele for that gene, and that it appears on one chromosome of one individual. That allele will have a frequency of 1/8 in that population, so if it is lost, the frequency change will be 1/8. Now imagine a population of eight individuals; the frequency of the new allele would be 1/16, so if it was lost, the change in frequency would be less than in a population of four. It should therefore be easy to see that the effect of genetic drift on allelic frequency change is dramatically less in very large populations. In fact, in an essentially infinite population, genetic drift would have a negligible effect on the frequency of an allele. Another factor that can influence allele frequency, and which is a part of genetic drift is non-random mating. If an organism does not have an equal probability of mating with any other organism in a population, then some alleles will increase or decrease in frequency simply due to that. For instance, if a population exists over a large geographic range, individuals that live closer to each other have a greater probability of mating than those who live far apart. Species who employ reproductive strategies such as leks,where males gather together and compete for the privilege of mating with females are also examples of non-random mating. Lekking increases the effects of drift because it reduces what biologists call the effective population size, or the number of breeding adults. For the above reasons, when population geneticists want to study factors that affect the frequency of an allele (such as natural selection), and they want to minimize the effects of drift, they model populations that are very large (essentially infinite) and assume random mating.
Can populations evolve?
Evolution is the change in allele frequency over time in a population of organisms.Short answer, populations are the only thing that evolves. Individuals die. Traits are passed on to progeny that make up the variations in the populations that evolve.
What is the probability that a new allele will be lost in the next generation?
New alleles are the result of mutation. When that allele appears in the population, it is at a very low frequency, and can be lost very easily. For example, consider an allele arising in an individual. Half of his gametes will contain the allele. Therefore, his offspring (assuming, of course, he finds a mate and has any offspring at all) only have a 50% chance of carrying the allele. If he from a species with low fecundity, there is a very good possibility that none of his offspring will have the allele and it will be lost from the population. It is estimated that only 1/3 of new mutations make it into the next generation because most are lost due to chance factors.
What are two processes through which genetic drift can occur?
Random events in small populations and the founder effect. The first can be just about any thing, but the second is about the emigration of a part of a population to another area/population. These emigrants are not fully representative of the parent populations allele frequency; hence drift.Other causes of genetic drift:1- Changes in allele frequency: Sometimes, there can be random fluctuations in the numbers of alleles in a population. These changes in relative allele frequency, called genetic drift, can either increase or decrease by chance over time.Typically, genetic drift occurs in small populations, where infrequently-occurring alleles face a greater chance of being lost.2- population bottleneck : Genetic drift is common after a population experiences a population bottleneck. A population bottleneck arises when a significant number of individuals in a population die or are otherwise prevented from breeding, resulting in a drastic decrease in the size of the population.3-Distribution: How does the physical distribution of individuals affect a population? A species with a broad distribution rarely has the same genetic makeup over its entire range. For example, individuals in a population living at one end of the range may live at a higher altitude and encounter different climatic conditions than others living at the opposite end at a lower altitude.4- Migration: Migration is the movement of organisms from one location to another. Although it can occur in cyclical patterns (as it does in birds), migration when used in a population genetics context often refers to the movement of individuals into or out of a defined population.5-Random chance
How is directional selection related to evolution?
Directional evolution is where one allele is selected in a population over another allele. Imagine a certain breed of dog that live in cold weather, they will have genes for thick fur (allele A), they are still caring allele for thin fur (allele a), but its recessive and animals with thin fur often dont make it. So if you looked at a distrubition in a population of these animals you would see a preponderance for A alleles and very low level of a alleles. Now imagine that over time their habitat changed and they no longer need the thick fur, in fact its detrimental to the animal to have thick fur. You would see a allele distribution shift from most animals having genes A to genes a. Even if a is recessive to A, if all the animals with thick fur die out then only those with thin fur can survive.
Is the human brain finished evolving?
Possible not, but if we were in a evolutionary cul-de-sac how would we know? ( evolution is only the change in allele frequency over time in a population of organisms. It is blind, has no direction and is not progressive or linear. Evolutionary predictions are by definition impossible to make )
What does the q represent in hardy-weinberg equation?
It depends on what you make p equal to. P is usually the frequency of the dominant allele, which makes q the frequency of the recessive allele, but they can be switched. As long as p is one frequency and q is the other, the formula will work. So if you have the dominant allele frequency (A) =.6 then the recessive allele frequency (a) =.4, because p+q=1 When you plug the frequencies into the hardy-weinberg equation p^2 +2(p)(q) + (q)^2 = 1 then you have (0.6)^2 + 2(0.4)(0.6) + (0.4)^2 = 1 (0.6)^2 = 0.36 which is the frequency of dominant homozygotes 2(0.4)(0.6)=0.48 which is the frequency of heterozygotes (0.)^2 = 0.16 which is the frequency of recessive homozygotes If you have a population of 100 people, these frequencies would mean that: 36 people would be AA 48 people would be Aa 16 people would be aa Which would mean that 36+48=84 people would exhibit the dominant trait and 16 people would show the recessive trait.
How do you use recessive allele in a sentence?
The building blocks of our genes (that make us what we are) are called alleles and these can be either dominant, recessive or codominant - which means they are equally dominant. Now for your sentence: "A typical example of codominance can be found in blood types, where the existence of A as well as B alleles in a person will lead to blood type AB".
How are the terms genes locus and allele?
1. A gene is a piece of DNA that provides a set of instructions to a cell to make a certain protein, a locus is a specific position on a pair of homologous chromosomes, and a allele is any of the alternative forms of a gene that may occur at a specific locus.
