Questions tagged [allele]

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

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19
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1answer
2k views

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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4answers
579 views

How does the molecular machinery choose where to cut a chromosome for recombination?

I'm wondering about a few technicalities of crossover in meiosis. The point of crossover is to create new chromosomes that don't have the same allele combinations as the original two chromosomes. ...
10
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4answers
1k views

Can sexual reproduction create new genetic information?

Is there a small chance that in sexual reproduction a new allele forms in the off-spring that was not present in either of the parents, or are the alleles in the offspring always from at least one of ...
8
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2answers
2k views

Are alleles equally sized?

If alleles occur at the same locus on a chromosome, does that mean they are of the same size? I was under the impression that they were, but I saw a gel electrophoresis testing different alleles of ...
5
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1answer
10k views

Ancestral Allele explanation

I'm having some trouble understanding the concept of ancestral allele. What exactly does it mean? What does it have to do with Identity by descent/state? What does it have to do(if anything) with SNP'...
5
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1answer
76 views

How allele is related to trait that is more complex than two cases (ex. height)?

Recently I started to learn about evolution and genetics. Simple stuff at the beginning - some videos, some reading. So far, everything seems to be pretty simple and straightforward. I easily grasp ...
5
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1answer
1k views

Microsatellite shifts (peak calling) GeneMapper! Thesis help!

I'm a masters student attempting to conduct a parentage analysis on a population of fish for my thesis. My advisor and post-docs haven't been very helpful, so I need some help! I have dinucleotide ...
5
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1answer
755 views

Mitotic crossover happens in G1?

I was reading this article in wikipedia and came across this : It has been suggested that recombination takes place during G1, when the DNA is in its 2-strand phase, and replicated during DNA ...
5
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1answer
94 views

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 ...
4
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1answer
788 views

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....
4
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0answers
383 views

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: ...
3
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3answers
8k views

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. ...
3
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1answer
68 views

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 ...
3
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4answers
2k views

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. ...
2
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2answers
2k views

Genetic mutations and new alleles

Amongst silent, nonsense and missense genetic mutations, is the latter the only one that leads to the creation of new alleles? If we define alleles as a specific form of a gene, and a gene as a ...
2
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1answer
6k views

Albinism inheritance problem: what are the father's alleles if he got an albino kid?

Albinism is caused by a recessive gen "c". A normal man marries an albino woman. The first son happened to be albino. What are the possible phenotypes of the parents? What is the chance that their ...
2
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1answer
74 views

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 ...
2
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1answer
298 views

Relationship between genetic diversity within and between species

Here is a quote from Wagner (2008) A second line of evidence [against neutralism] comes from the relationship between the mean number of polymorphic differences between alleles within a species, $\...
2
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1answer
7k views

Calculating pairwise Fst from allele frequencies

I am trying to refresh my memory on population genetics for a project, and I'm having some trouble. Assume I have genetic data on 3 populations with 5 individuals in each of a given species, with the ...
2
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2answers
898 views

Recessiveness of allele for protection of organism

Heterozygous organisms profit from pairs of gene alleles. Harmful alleles when being recessive can be carried without any harm for the organism. Only when two harmful recessive alleles form a gene the ...
2
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1answer
1k views

Recessive alleles at Hardy-Weinberg equilibrium

I've run into a question that I disagree with others on but I would like to receive the input of others. The question is: If a population is at Hardy-Weinberg equilibrium, which of the following can ...
2
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1answer
332 views

Genetics independent assortment?

As indicated in this question, what do you think is is the best explanation for the observed progeny, is it because distance between genes affects recombination frequency? My main concern is question ...
2
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2answers
3k views

Genetic Epistasis Question

I need help with this practice question. I'm assuming that would a epsitatic recessive question since the parents are true breeding and then the ratio would be 9.3.4. But I am not so sure. Any help ...
2
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1answer
2k views

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 $1$, $...
2
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1answer
3k views

How to recognise the type of allele by pedigree analysis diagrams? [closed]

It was said that this interference pattern is due to dominant allele. I fail to see that. In general how to recognise the type of allele by pedigree analysis diagrams?
2
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2answers
163 views

Chance of child inheriting at least one copy of an allele - heterozygote mother, unknown father

Our genetics professor has posted up working for previous examination answers, but I am not convinced that his answer is correct. My answer is close but may just be due to co-incidence. Question: ...
2
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1answer
346 views

Mode of Enzymatic Inhibition via R-Allele

The photo above shows the effects of the R allele of the pea shape gene on the synthesis of an enzyme that converts unbranched starch into branched starch. The r allele of this gene determines an ...
2
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0answers
16 views

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 ...
2
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0answers
42 views

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 ...
2
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1answer
106 views

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 ...
2
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0answers
34 views

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 ...
2
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0answers
59 views

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 - ...
2
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0answers
60 views

What is the best test for SNV clustering?

I am looking for a method to cluster single nucleotide polymorphisms based on clinicopathologic data (mainly receptor immunoistochemistry). So far, I've came up with only two that handle dummy ...
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2answers
161 views

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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2answers
539 views

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 ...
1
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2answers
420 views

Recessive is Dominant to Dominant?

If a gene has for instance three alleles, p, q, and r, then could p be dominant to q, q be dominant to r, but r be dominant to p? Can a gene that is recessive to one allele not be dominant to another ...
1
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1answer
3k views

Why do almost all SNPs have two alleles?

Reading the Wikipedia page for SNPs I find the sentence "Almost all common SNPs have only two alleles." This is consistent with terminology elsewhere, such as the therm "Minor allele frequency", which ...
1
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1answer
149 views

Quantitative Traits Genetics

Can someone please help with this question? I'm not so sure whether part A should be 11 inches or something else. Also, is part B correct
1
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1answer
631 views

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 ...
1
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1answer
91 views

Alleles notation in SNPPedia criteria

I can understand the allele notation when is in the form rs8176719(T;T) or rs8176719(G) but recently i found this ones rs8176719(T;-) or rs8176719(-;T). So im confused, rs8176719(T;-) is the same as ...
1
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1answer
135 views

Population Genetics Question

Can someone please help with this question? Here is my working (just in case it is not clear: 1/300*1/30*1/2) but is this actually correct or do I need to multiply by 0.5 once again? I appreciate any ...
1
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1answer
473 views

Gene Complementation Question

Hi everyone! Here is a diagram of a genetics complementation problem. My main concern is regarding number 3d. I'm assuming that in this case, it would be complementary interaction and thus exhibiting ...
1
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1answer
46 views

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 "...
1
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0answers
76 views

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 ...
1
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0answers
28 views

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 ...
1
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0answers
577 views

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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0answers
62 views

“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 ...
1
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1answer
692 views

Why does allele linkage cause disproportionate phenotypic ratios? [closed]

I was learning about allele linkage in Biology class and I got confused by the resultant phenotypic ratios. Say you have a dihybrid cross BbGg x BbGg. The Punnett square would look like the ...
0
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2answers
52 views

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....
0
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1answer
313 views

What are multiallelic genes?

Is there a clear detailed description for multiallelic genes? Are they simply genes that are more than two alleles?