Questions tagged [genetics]

Genetics is the branch of biology that deals with the transmission and variation of inherited characteristics.

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Interpretation of arrow-sense heritability over one (using R/S = h^2)

Here is my data: Mean height score of the total parental population: 5.2 Mean height score of selected parents (those chosen for breeding due to their higher height): 6.4 Mean height score of the ...
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1 answer
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Method of determining base values of traits in isolated populations

Prelude: I came across a discussion about the correct formula for calculating the average IQ of offspring, which goes something like the following $$ 100 + \frac35 \left( \left(\text{father's IQ} + \...
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What is important in the Luria-Latarjet effect?

In the seminal paper Luria, S.E. and Latarjet, R. (1964) “Ultraviolet irradiation of bacteriophage during intracellular growth”. Proceedings of the National Academy of Sciences of the United States ...
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Evolution of the human Y chromosome

This recent news article suggests the number of genes in human male Y chromosome has steadily been reducing in the Y chromosome for a long time and is in danger of dying out all together. What I want ...
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Why do we choose to use agar instead of agarose in various microbial applications?

When performing gel-electrophoresis we always use agarose. Is there a reason we can't perform it using Agar? And in microbial culture Agar is commonly used as solidifying agent, could this be replaced ...
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Pedigree Analysis

I was doing some pedigree work and couldn't figure out why my answer is wrong. This chart is supposed to be an autosomal Dominant method of inheritance, but I am finding an autosomal recessive pattern ...
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Is there a program that demonstrates overall fitness will increase in a population overtime?

Of course this will not always be the case with environmental factors, but generally speaking. I'm searching for a program that shows evolution works from a statistical standpoint.
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With CRISPR-mediated gene editing, can the PAM for the guide RNA also be site of the desired edit?

I'm hoping to use CRISPR-Cas9 in yeast to change a single nucleotide in a gene of interest. While there are a couple potential guide RNA sequences I could use, the best option's PAM sequence (TGG) it ...
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1 answer
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What is the word for a small (under 50 bp) structural variant?

What is the word for a small (under 50 bp) SV? Perhaps it is MNV (multi-nucleotide variant)? Something like microindel? I do not like SNV as "single nucleotide" is not really correct and I ...
2 votes
1 answer
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Why are multiple copies of the 35S enhancer used for overexpression in plants?

I know that the CaMV 35S promoter is widely used for transgenic plants, where it acts as an enhancer element for constitutive overexpression. I noticed that it is always used as a tandemly repeated ...
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Patterns of craniofacial topology

There are animals which are not directly related but have similar craniofacial topology. For example: koala, donkey, mouse, turtle, parrot all have features seemingly belonging to same topology, ...
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Preserving a sample for mtDNA and nuclear DNA analysis

Imagine a person in the early half of the 20th century (1900 to 1950) took some kind of sample(s) from a living human body using any technology of the era. They then stored it using any technology ...
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How to resolve the contradiction between the time required for the fixation of neutral mutations and the time available according to the fossil record

More than thirty thousand synonymous single-nucleotide-substitutions have occurred in protein-coding genes in the human genome since the human lineage diverged from the chimp lineage ~7 million years ...
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Have there ever been "half-twins" who were halfway between siblings and twins?

Have there ever been two human siblings who were 75% or more genetically related?
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Reading genotype aloud

For this genotype, P2ry12$^{+/+}$ I read it "P2ry12 wild type." For animals with the GFP being expressed under one Cx3cr1 promoter, Cx3cr1$^{+/GFP}$, how do I read that aloud? What about for:...
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Gene Mapping - Please explain in Lay terms

Taking an AP bio course, and for some reason I cannot comprehend the mechanism of how one determines the location of alleles on a chromosome. The math is simple and I can memorize it, but its bugging ...
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Has perturbation theory been applied to mutation process frameworks?

For example, imagine this Feynman diagram: This is analogous to mutational homoplasy. When comparing haplotypes, there are many possible tree topologies. Under maximum parsimony, we ignore suboptimal ...
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Production method of custom seed mir451? How to edit middle of a fragment?

I am trying to create a plasmid that produces mir451 targeting a new gene, so I need to alter the seed sequence. The seed sequence is 7 bp long, so I think that is too long for PCR mutagenesis. How do ...
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Why is the expected time to coalesce the same as the ploidy times inbreeding effective population size?

The expected time to coalesce, in generations, is the same as the ploidy (e.g., 2 for humans) times Nef, the inbreeding effective population size, under coalescent theory. Why? Both ploidy * Nef and ...
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How many people need to have the same mutation of a gene in order for that gene to be seen as a feasible candidate for a disease?

I am learning about genome-wide association studies (GWAS) and I know that they are used to see whether certain SNPs are associated with a disease of interest. From everything that I have watched and ...
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2 answers
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What are the chances that two children of the same couple will have the same genes without being identical twins?

If I randomly select half the chromosomes of the male and female eventually I will select the same exact half for both a second time. How often does this occur? Is this considered a twin if it is born ...
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How exactly are the eye color genes related?

How exactly are the gey (maybe aka EYCL1?), bey(2?) (aka EYCL3?), HERC2, and OCA2 genes related to each other? There are numerous sources that explain eye color in terms of OCA2's role in the creation ...
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How did the Zinder-Lederberg experiment on Transduction work?

In the paper that introduced TRANSDUCTION (J Bacteriol. 1952 Nov;64(5):679-699), Lederberg and his student Zinder reported that S. typhimurium "LT-22 is lysogenic for a virus active on LT-2. ...
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Calculating pitch of B-DNA

From this question (How pitch of a DNA Helix is 3.4 nm?), I've learnt that for counting the number of axial rise for 10 base pairs in 1 helical turn to measure the pitch of B-DNA, we have to include ...
3 votes
2 answers
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Change of DNA concentration due to restriction digest?

Assume that you perform a restriction digest in a molecular biology lab: you combine genomic DNA, a restriction endonuclease (e.g., EcoRI), and the optimal buffer for that endonuclease and are about ...
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How does positional memory in fibroblast cells work?

I have a question regarding how positional memory in fibroblasts work, specifically, where the memory comes from/how its made. For example, the Salamander & other amphibians are able to regenerate ...
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Bacteria genetic screen for mutants

Is there a simple screen for bacterial mutants with increased mutation rates? For example, detection of some loss-of-function mutation that causes increased mutation rates. Any screen I can think of (...
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Coefficient of fraternity between grandparent and grandchild from full-sib parents

I have the following pedigree and I would like to calculate the coefficient of fraternity between individual 1 and 5. R/AGHmatrix::Amatrix gives a coefficient of 0 for this pair. Shouldn't it be non-...
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What is a good expression vector for Salmonella enterica subsp. enterica serovar typhimurium

I am interested in expressing custom proteins in a Salmonella strain, however I am facing difficulties in finding the appropriate expression vector for it. It seems that most of the resources provide ...
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What software can be used for simulating human meiosis, taking linkage and recombination into account?

I want to study the nature of genetic variation in offspring from the same set of human parents. To this end, I would like to take two (male and female) complete genomes, generate gametes from them, ...
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3 answers
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Is there any objective way to describe ethnicity?

Is there any objective way to describe ethnicity that does not rely on arbitrary sociocultural concepts like referring to racial constructs, modern nations like “Spanish”, or even continents like “...
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How to calculate df in the chi-square test of Hardy-Weinberg equilibrium? [closed]

We often use df=1 in Hardy-Weinberg equilibrium when there are only two alleles. Some people say that it's because we've used the frequency of two alleles when calculating the expectated values, while ...
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Is there a convention regarding the use of forward vs reverse DNA strand to represent DNA sequence?

I see in this paper the notation IL-1A C[-889]T which suggests that for this gene, the reference allele is C and the variant is T. However, when I look up the same gene on dbSNP, it says the alleles ...
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Analysis of post transplantation lineage tags

I'm having some trouble understanding some bits of a study, mostly about the Sleeping Beauty system and TARIS model, from this paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408613/ I ...
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What is the exact definition of the term 'trait'?

A trait is a characteristic shown by an organism. For example a Tt plant would show the 'tallness' trait. It seems to me that, by analogy, sickle cell anaemia (SCA) carriers should show the 'normal' ...
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Why is the maximum propotion of MII 2/3 in the ordered tetrad analysis? How is it different from normal recombination?

My textbook says that the maximum propotion of MII gametes in the ordered tetrad analysis is 2/3, and if we put it into the formula RF(recombination frequency)=MII/2(MI+MII), we can find out that the ...
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Is there potential to modify GM crops to inhibit their reproduction with non-GM crops?

I've been reading on terminator gene sequences and was wondering whether the same technology could be applied to GM crops to prevent transgene flow. Turns out Monsanto had developed the technology but ...
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Is gut bacteria Succinivibrionaceae's low methanogenesis understood well enough for GM of cattle gut bacteria to be considered?

After watching the Periodic Table of Videos episode linked in this question I watched the episode Wallabies and Methane where Sir Poliakoff says (a bit after 02:00):...
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Are Hardy-Weinberg equilibrium assessment for two alleles on one loci or two locus?

Are Hardy-Weinberg equilibrium assessment for two alleles on one loci or two locus? For instance, when the video says BB Bb bb https://www.khanacademy.org/science/ap-biology/natural-selection/hardy-...
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Are mutations random?

The following claim Mutations are random or just the use of the expression Random mutations are very common among lay people. The claim is very common among lay people. The claim is often ...
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Hardy-Weinberg Equilibrium Test Result for Merged Genotypes

I was curious if two populations are in Hardy-Weinberg Equilibrium (HWE), and if they are merged, then what happens? To find out, I considered populations from the 1000 genome project data. For ...
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Is the amount of pigment in one feature (e.g. hair, eyes, skin) connected to the amount of pigment in another?

Let's say, genes allowing it, you have a red-haired child with hazel eyes. The hair is a darker/deeper orange color, so (if I recall correctly) having some degree of eumelanin—not much compared to ...
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How frequently does recombination occur, and how long are the recombinated fragments?

I understand the mechanics of recombination, but am struggling with the 'scale'. When two homologous chromosomes pair, roughly how many recombination events occur on average? I understand there will ...
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Can a person have different sex at cellular level?

I mean like every cell has a sex chromosome.So does a male with XY chromosomes has all the cells in all the organs inside his body of XY chromosomes only? And vice versa.....
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Calculation for underlying genetic value of a phenotype given parents genetic values

What is the most accurate way to calculate a child's genetic predisposition to a phenotype, given both parents' genotypic predispositions? Assume trait X is 50% heritable and controlled by an ...
3 votes
1 answer
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How to interpret this statement on missing heritability

I'm currently studying a behavioral genetic course, but still, I feel that I'm lacking many basic concepts. A particular topic I don't understand is missing heritability. Here's an example regarding ...
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Use of plasmid pXen5 for transposon screening

I would like to use the plasmid pXen5 (by Xenogen) for a transposon screen. It contains two inverted repeat sequences, with Luciferase, Kanamycin, and the transposase itself in between. (It's tn1409). ...
3 votes
1 answer
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What is an intuitive explanation of linkage disequilibrium?

Is it possible to give a simple and intuitive explanation of the concept of linkage disequilibrium? You know, so I can sort of sound like I know what I'm talking about. Everything I read about it has ...
3 votes
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Recombination Data Set

I was looking over some genetics question and came across this data set. In the fruit fly Drosophila melanogaster there is a dominant gene b+ for grey body color and another dominant gene c+ for ...
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How many base codes are in DNA? Two or four?

We know there are four bases found in a DNA: adenine (A), cytosine (C), guanine (G), and thymine (T). We also know that A always pairs with T and G always pairs with C. Can we say that the DNA is ...

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