Questions tagged [allele]

Alleles are different forms (among many possible alternative forms) of the same gene.

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Hardy-Weinberg principle

The following paragraph on Wikipedia about the Hardy-Weinberg principle is bothering me. It should be mentioned that the genotype frequencies after the first generation need not equal the genotype ...
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Why are parents of contrasting genotypes involved for a reciprocal cross?

In a reciprocal cross, we try to determine whether a trait is sex-linked Or not... One thing I couldn't understand was that, why are parents of contrasting genotypes involved? Does that mean that at ...
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Do we come to know which allele is dominant by seeing family genration tree only?

I know that a Gene has Alleles (variation) and one is Dominant over Other i.e the Other Recessive. Then I got a Thought that How can we tell whether an Allele is Dominant or Recessive...... and I came ...
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Can alleles have cyclic dominance?

Do the relationships between alleles always form a hierarchy? Ignoring partial and codominance, can alleles have a cyclic relationship? For example, is there anything that exists analogous to the ...
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Alleles and Ploidy [closed]

I was recently studying inheritance and variation and came across a sentence: A diploid organism can show only two alleles How is this possible?
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Are probabilities of mutations symmetric?

For the premise of this quiestion let's assume that there is an allele A and an allele B. The allele A has a probability P to mutate into the allele B in the given timeframe. Is it also true that the ...
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Question regarding the number of alleles

Why is it that in biology we often say that a gene has two alleles? When we analyze allele frequencies (e.g. using Hardy-Weinberg Equilibrium), formulas are often generalized for two alleles of a gene....
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ABO allele frequencies: Why use the EM algorithm?

In textbooks and lecture notes and slides posted online, determining allele frequencies using blood type information (ABO), under the assumption of Hardy-Weinberg equilibrium, is accomplished using ...
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Will a less favorable allele's frequency go to 0?

For example, a pond is dark in color. There are two alleles. The dark color allele is dominant over the light color one. Let's assume that the relative fitness of both the homozygous dominant and ...
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What is an allele?

According to the entry for allele in Wikipedia: “An allele is a variant form of a given gene, meaning it is one of two or more versions of a known mutation at the same place on a chromosome.” ...
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Do some genes follow Rock-Paper-Scissors model of dominance?

Assuming there are at least 3 alleles of the gene $G$ in total - $G_R$, $G_S$ and $G_P$ - is there any gene for which the following is true? $G_R$ is more dominant than $G_S$. $G_S$ is more dominant ...
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Easy Hardy Weinberg Equilibrium [duplicate]

Hi My friend and I get 2 different answers to this question. I would like to know how to calculate the value of q. My friend says that 500/1500=q because there are 500 recessive alleles in the ...
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How to determine if two mutations in a gene are on the same or different alleles?

I would like to know, except a familial study, is there another way to determine if a mutation/variation is cis or trans (i.e. on the same or different alleles)? For example by sequencing technique or ...
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is it possible for a son to inherit an allele on a Y chromosome?

Obviously, the only way for one to be male is to inherit the Y chromosome, but are there alleles on the y chromosomes? Or is it just automatically the recessive trait without an allele.
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What is the cause of “imbalanced” linkage disequilibrium?

With perfect linkage disequilibrium ($D' = 1, R^2 = 1$), you might have the following table of counts for the alleles: B b A 100 0 a 0 100 With "...
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My understanding of chromosomes and the processes related to them is lacking [closed]

I'm sorry for the incredibly simple question, I just can't seem to find any answers elsewhere online. I am a high school student currently studying for the upcoming AP biology exam, and recently I ...
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Are there only a few alleles or groups of many alleles impacting protein structure and function?

I'm in the first year of Medicine and I'm studying Genetics and Evolution. I have this doubt in the back of my mind and I'm not being able to move forward without someone explaining me what's wrong ...
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Does the law of independent assortment apply to homologous chromosomes or alleles, or both?

My textbook is giving me two definitions 1st def: "random orientation of homologous chromosomes at the metaphase plate in meiosis 1." 2nd def: "alleles for one gene separate into gametes ...
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How can inbreeding be used for selecting mutations?

I understand that inbreeding, after a number of generations of crossing genetically related individuals eventually yields homozygotes, however I can't seem to understand how it can be used for ...
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GEN file format, SNPs and alleles

I have a few questions I can't seem to get a straight answer to, regarding the .gen file format and also biology in general. The ...
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Is there a practical upper limit to ploidy?

In my AP Biology class, we were discussing polyploidy, specifically, its deleterious nature in mammals and its prevalence in plants. We also learned that commercial crops, especially fruit, are often ...
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For allele frequency determination, is it good to take samples from a college/school or a hospital or any other technique?

I am trying to determine allele frequency of a hla allele. Preliminary analysis shows the prevalence of the allele (homo or heterozygous both) is 3%. The allele is related to a disease (After exposure ...
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Is bi-allelic gene expression random?

Supposing we have the genotypes “Aa”, “AA”, and “aa”... which are not mono-allelic (not imprinted and not X-inactivated). Does the dominance of the “A” allele over “a” allele affect which gene is ...
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Finding specific genotype occurrences given allele frequency

So let's say I have a tetraploid species and I have 4 possible alleles for a particular locus. I have found that I can have 35 total possible genotypes and I know the allele frequencies for each of ...
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Gene expression: which allele is considered?

For human beings, we have two copies of each gene inherited from the parents. The question is, when referring to gene expression, which copy (or allele) is considered?
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why and how multi allele gets reported during variant calling in vcf?

This might be a very basic question for many here. With the basic understanding of inheritance, eventhough there is a possibility of multiple genotypes due to multi alleles, the resulting genotype can ...
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Genotypes of gametes produced by an F1 individual?

I have an urgent question as I have an exam tomorrow. I was skimming some past exam papers and one question came up which has me completely confused. A cross was made between a pure breeding diploid ...
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Impact of Natural Selection on Population Size

I have conducted a lab with my IB Biology 11 class, regarding changes in allele frequencies within generations overseeing the natural selection of an advantageous phenotype. We were looking to ...
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Simple Autosomal Recessive question by a novice genetics student

How do you figure the percentage of offspring that will be a carrier of an Autosomal Recessive gene when the FATHER is the recessive carrier and the MOTHER is not affected (normal, no recessive)? ...
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Are mutations the cause of alleles?

For example, some leopards have a mutation which causes black fur. So Black fur and normal fur colour (orange-white) are both alternate forms of the same gene, right? So does that mean that mutations ...
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Hardy-Weinberg sex linked formula

The "big five" assumptions are the ones listed in the main text. However, the basic formulation of Hardy-Weinberg equilibrium also relies on a few other assumptions; Allele and genotype frequencies ...
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How does allele dominance work in polyploid organisms?

You know how there are tables to demonstrate allele dominance in diploids, such as the table found in this question? Well, I was wondering how this works with tetraploids, hexaploids, octoploids, etc....
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How does sexual reproduction generate more genetic variation?

I'm curious as to why sexual reproduction generates genetic variation. For me, the term genetic variation is a little ambiguous. The way I understand it, it's the number of alleles at a locus in a ...
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Hardy-Weinberg for triploids

Problem: A certain species has somatic cells with ploidy 3n (the organism inherits three sets of homologous chromosomes from each of three parents). At a certain locus, there are three possible ...
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Is protein production doubled if you have homozygous dominant genes as opposed to heterozygous genes?

At school we were taught in quite simplistic terms. We were told that there is a dominant and recessive type of every gene and that if the dominant gene was present, the protein is produced and if it ...
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How does selection affect allele frequency?

Question People who are carriers for Blooms Syndrome have developed a selective advantage. How would this affect the allele frequency of the disease allele? My thoughts Natural selection will ...
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how can a recessive allele become represented in a significant number of individuals in a population

Darwin believed that individuals that are poorly adapted to their environment are less likely to survive and reproduce. This means that their genes are less likely to be passed to the next generation. ...
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When to decide that two similar sequences are different genes or not?

Working on RNA-Seq data directed me to ask this question. In RNA-Seq jobs, after de novo assembly we have lots of transcripts with different rates of similarity (0 to almost 100 percent) that we ...
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1answer
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Dominance coefficient

I am trying to understand the meaning of the dominance coefficient. I'll be more specific to what I don't understand, in a moment. Let $A_{11}$, $A_{12}$ and $A_{22}$ be genotypes with fitnesses $1$, $...
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How many allele for one gene are found inside our cell? [closed]

I know it depends on phase. So i am talking of - 1) in human (diploid organism) with cells before prophase (before replication, when 23 pair of homologous chromosomes are present ). I think answer is ...
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1answer
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Chromosome related problems.

1.) How many versions (alleles) of a gene can we carry if every chromosome is in pair? 2) What happens during the gamete formation (meiosis) ? Do the gene pairs stay together? 3) What happens then ...
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What is a gene transcript, how is it different from an allele?

Within human genetics, My current understanding of a transcript for a particular gene is that it's the exact nucleotide sequence and position of a particular instance of said gene in some individual. ...
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What is allele-specific binding?

So far all I have found is this: https://www.biostars.org/p/132527/ My guess is that some alleles, for whatever reason, bind to things like transcription factors 'moreso' (for want of better word - ...
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What are multiallelic genes?

Is there a clear detailed description for multiallelic genes? Are they simply genes that are more than two alleles?
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Minor Allele Frequency (MAF) higher than 0.5? [closed]

I have a set of data in PLINK format (*.bed, *.bim and *.fam files). There are around 2000 individuals in my dataset. I used PLINK to calculate allele frequencies in the population: ...
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Is this how female and male gametes look like in plants?

In the red box, the pink one is female sex cell I presume and the blue one is a male sex cell. http://prntscr.com/dsii2x Am I right? or are these chromosomes.. I'm confused. This is law of ...
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Is the term 'allele' specific to sexual populations?

I had always thought that 'allele' simply meant a variant of a gene and thus could be used in the context of either asexual or sexual populations. With it only being slightly less useful as a concept ...
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Interpreting Allele frequency and allele count

In the following vcf file, the AF allele frequency of ALT allele is 1.0. Does it mean that it is not a true SNP of interest? Does it also mean that ALT allele always occurs and REF allele never ...
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Passing on Alleles

Just a basic question on alleles, I am just trying to learn the basic concepts. So if we are to screen two parents, both with one dominant and one recessive allele for a given characteristic e.g. eye ...
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“Genotype structure”?

What does a geneticist mean when they write "genotype structure", e.g. the sentence "...represents continuous allele frequencies for both tumor and normal samples, while leveraging the expected ...