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Why are dominant alleles that cause lethal disorders less common that recessive alleles that cause lethal disorders?
Wiki User
∙ 11y ago
A lethal dominant gene prohibits the organism from reproducing irregardless of the paired gene, so it is removed from the gene pool as soon as it appears. A lethal recessive gene, on the other hand, does not prevent reproduction unless it is paired with another lethal recessive, so it may be passed down through many generations before becoming paired and preventing reproduction.
Wiki User
∙ 13y ago
Wiki User
∙ 11y agoBecause everyone who gets a lethal dominant allele is dead.
If a lethal mutation is recessive, a heterozygous organism can inherit the allele and reproduce, ensuring the preservation of the allele in the population into the next generation. If the mutation is lethal dominant, it dies with the person who inherits the allele.
Wiki User
∙ 13y agoIn many cases, the heterozygous condition has a certain advantage. When this is the case, the recessive allele is maintained in a population because it appears in the heterozygotes. Sickle cell anemia is a classic example in that the heterozygotes have a resistance to malaria.
Wiki User
∙ 11y agoIf a dominant allele is lethal then every individual who has one copy of this allele will die. This means that these individuals are extremely unlikely to reproduce.
However, if the disorder is caused by a recessive allele, a person needs two copies. This means that people with one copy can still reproduce, and so the gene is more frequent than the dominant lethal gene.
If the lethal allele is dominant - that means that an individual will die if they have one or two copies of the allele.
However, if it is recessive, then heterozygous individuals (those with only one lethal allele), should not die from that disorder. This means that the recessive allele is much more likely to be passed on, as the individual is more likely to live long enough to have children.
the lethal dominant alleles kill the carrier before they can be passed on. lethal recessive will not.
Wiki User
∙ 13y agoBecause lethal dominant alleles typically kill the carrier before they can pass the genes to their offspring.
Wiki User
∙ 12y agoIn diploid organisms, if there is one recessive and one dominant allele of a gene, then the phenotype will be determined by the dominant allele.
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What is the difference between dominant and recessive gene?
There are no such things as dominant and recessive genes. There are only dominant and recessive alleles. Dominant alleles are parts of a gene that present its features over the recessive allele, which is the one that is always masked by the dominant allele. The recessive allele's trait only shows if both of the alleles in a trait are recessive.
Disorders caused by recessive alleles?
Many different types of disorders can be found if multiple alleles occur, for example, if your have 3 number 21 chromosomes, then you will have a disorder called "Down Syndrome", so the answer is "Yes".
Why can people pass on traits that don't show up in them?
some traits are more common and getpast on easier There are dominant and recessive traits- Each person has 2 copies of a gene that codes for a certain trait-this is called the genotype (one from mom and one from dad) Whichever trait is Dominant will be expressed- or passed on to you- for instance darker pigments are usually dominant over lighter pigments so if a person has genes for blue and brown eyes- they will most probably have brown fair skin or dark skin- probably dark red hair or black hair- black
Why are dominant genetic disorders rare in humans?
Intuitively, natural selection should eliminate these lethal genetic disorders from the population.....However, natural selection does not act on the genotype of an individual, but on the phenotype. Many of these lethal genetic disorders are the product of two "recessive alleles" that were masked in the parents with a "dominant allele."
Is colorblindness a dominant or recessive trait?
Color blindness is an inherited trait that can be passed on through reproduction but it has some peculiarities. It is recessive and not very prevalent in the gene pool. Because of this, color blindness does not appear very often in the population. In addition, it is a sex-linked gene on the X chromosome. Thus males only have one gene to express color vision. If it happens to be the recessive allele, then males are color blind. Females, on the other hand, must have both alleles recessive in order to be color blind.source: ciese.org/curriculum/genproj/activity35.html
What do dominant and recessive alleles have in common?
Alleles are different types of a gene. Each gene controls a characteristic and they is usually a recessive allele and a dominant one. The main similarity is that they both control a certain characteristic!
Why are recessive alleles not removed from populations over time?
If the recessive genotype is selected for more often than the dominant genotype, the recessive allele will become more common than the dominant allele in the gene pool.
What is the difference between dominant and recessive gene?
There are no such things as dominant and recessive genes. There are only dominant and recessive alleles. Dominant alleles are parts of a gene that present its features over the recessive allele, which is the one that is always masked by the dominant allele. The recessive allele's trait only shows if both of the alleles in a trait are recessive.
Why are recessive disorders more common than dominant disorders?
dominant traits show up in the first generation so any disorders have a 50% percent chance of showing up in offspring. recessive traits skip a generation therefore any diseases would have on a 25% chance.
What happens to A trait controlled by a dominant gene?
yes, if two Bb parents have kids, there is a 3:1 ratio that their children will show a dominant trait (BB Bb Bb bb). For multiple alleles (3 or more) it gets a little more complicated. Some traits, like height, have 1000's of genes affecting them. Consult your biology teacher for more information.Yes. Because to have a dominant trait you can have two dominant alleles or just one dominant and one recessive (because a dominant allele negates the effect of a recessive allele.) To get a recessive trait it takes two recessive alleles as oppose to a dominant trait where it takes only 1 to have a dominant trait. Therefore Dominant traits are more common.
The outward expression of a gene?
The outward expression of a gene is determined by the alleles. Alleles come and pairs, and the pairings can be heterozygous or homozygous. For homozygous (both alleles are the same) phenotypes, the trait you see is the same as the alleles. For example, if both alleles are for a white flower, the flower will be white. There are different outcomes for heterozygous (one dominant allele, the other recessive) phenotypes. In complete dominance (the most common), the dominant allele is the the trait you see. For example, the flower has an allele for red (dominant) and white (recessive), it will be red because red is dominant to white. In incomplete dominance, the dominant allele is not strong enough to fully cut out the recessive so trait will be a mix of both. In the flower's case, it would be pink because white will be seen through the red. In codominance, both alleles are expressed just on different areas. The flower would have both red and white splotches.
Why do recessive trail are more common in some cases?
They're not necessarily, but they can be. When a recessive trait is more common, it likely because it was advantageous to have that trait so the species evolved to have more of it in the gene pool. Also, since dominant traits are expressed over recessive traits, natural selection has more of an effect on them.
It is far more common to find human genetic disease caused by alleles than by alleles because?
You are repeating yourself. If a dominant gene inhibits reproduction, it will eventually work itself out of the population. Whereas a recessive gene can sporadically pop up. However, a gene such as a "cancer gene" might not inhibit reproduction, and thus could perpetuate at a higher rate in either a dominant or recessive form. There is a theory called "Heterozygote Advantage" that certain genetic disorders such as Cystic Fibrosis or Sickle Cell Anemia may actually provide a protective advantage when found as a heterozygote recessive, but is deadly when the person inherits both genes.
How can a sister with the same parents have different hair colors?
Yes, this is possible. The parents may not have the same hair color as their offspring, because the offspring could have the hair color caused by a recessive allele. This allele could have been present in an ancestor, but not shown up again because its frequency is not as common as another hair color
Is there any evidence that the trait shared by most or the population is not controlled by a dominant allele?
There are many traits that are found in the majority of populations that are recessive alleles. Conversely, some rare conditions are the result of dominant alleles. Dominant alleles do not dominate the population because of independent assortment. An example of a recessive allele is O type blood. O typ blood is the most common blood type. There are four types of blood (because typing is co-dominant) A, B, AB, and O. If you have two A alleles or an A and O, you have A type, if you have two B alleles or a B and O, you have B blood type, if you have an A and a B, you have AB, if you have two O's, you have O type. Looking at that, you would think a minority of people would have O but O is the most common blood type in the US population (It is not true of all populations, however.) Conversely, some rare diseases are controlled by a dominant allele Huntingtons, for example is dominant but the allele is rare. Polydachtly (extra fingers) is dominant as well but has not taken over the population because there is no advantage (and hasn't been selected-for) and because of independent assortment.
Why isn't the dominant gene's trait always the most common?
Statistical mating between mom and dad. Bb X Bb 1/4 of the time, statistically, you will get progeny with the alleles bb, the homozygous recessive traits.
Disorders caused by recessive alleles?
Many different types of disorders can be found if multiple alleles occur, for example, if your have 3 number 21 chromosomes, then you will have a disorder called "Down Syndrome", so the answer is "Yes".
