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

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Can two humans with 44 chromosomes produce viable offspring?

It is known that there are very few individuals having 44 chromosomes, not the usual 46 chromosomes. One example is a male in China: the first article, the second article. The other is a female in ...
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Two brown-haired people have two children, P and Q. P has blond hair. Q has brown hair. What is the probability that Q is heterozygous?

Two brown-haired people have two children, P and Q. P has blond hair. We therefore believe that each parent is heterozygous and that blond hair is a recessive trait. Q has brown hair. What is the ...
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What factors govern the variable age of onset in Huntington's Disease?

"Huntington's disease (HD) is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and psychiatric problems." As we all know, this genetic disease ...
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What are polytene bands, and why are they there?

Drosophila polytene chromosomes have been particularly useful in genetic research, as it made cytogenetic gene mapping possible with very little effort. This was primarily accomplished due to polytene ...
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What is the advantage of circular DNA in bacteria?

From what I understand, bacteria have circular DNA. What advantages does it have over linear strands like for eukaryotes? Do there exist bacteria with more than one ring of DNA?
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Mathematical Modelling of Natural Selection

I'm a math undergrad looking for some papers on modelling the process of natural selection. The only paper I've been able to find is by the pre-eminent mathematician Herbert Wilf from 2010, There's ...
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Chromosomes are of different size but why do all chromosomes have similar GC percentage?

When I browsed NCBI I saw a pattern: even if the chromosome sizes, number of genes, and number of proteins are different, GC% in chromosomes tend to be similar. The examples are linked below. Yeast, ...
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131 views

How do the variable portions of antibody genes look in cells which don't produce antibodies?

There are several families of antibodies found in mammals. They may have two or more antibody domains which contain heavy and light chains. The variable regions of the light and heavy chains genes ...
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Have any genetically altered organisms actually become abundant in a natural environment?

Most of the things that come up in Google and Google Scholar for this question have a mostly/completely speculative tone, or at best use models instead of measurements. This report describes some ...
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Are there eukaryotes without introns?

This question on the function of introns in eukaryotic genes made me think: I know that more basal organisms have smaller introns and fewer alternatively spliced exons compared to mammals. But are ...
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196 views

Definition of Dye- Reduction Test?

Can some one give a simple explanation or definition on what a dye-reduction test is.
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137 views

How might gene clusters like the lac operon evolve?

The obvious answer for a gene cluster is gene duplication and mutation of one or both genes. But the genes in the lac operon seem not be so functionally/structurally similar (as compared to the Hox ...
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50 views

How are geneticists able to isolate gene functions?

As an example, this Scientific American article describes a known area in the dog genome that metabolizes carbohydrates. How is it that researchers are able to determine specific functions such as ...
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Can mammals from different species reproduce?

I'm curious on how genetically different can two animals be in order to reproduce. Could they belong to different species? One example is the mule which is the offspring of a donkey and a horse, in ...
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95 views

What's the difference between a free chromosome fragment and an extrachromosomal array?

This is reference to a review on C. elegans mosaic analysis by Yochem and Herman, in which the authors make a distinction between free chromosome fragments and extrachromosomal arrays. For the ...
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344 views

What is the biological mechanism underlying caffeine intolerance? (CYP1A2 or other?)

As far as I can tell, caffeine metabolism occurs primarily via the CYP1A2 enzyme. I am curious as to whether mutations in the CYP1A2 gene are associated with caffeine intolerance. Some site that is ...
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How many nucleotide pairs code one gene?

As I know three nucleotide pairs (triplus) code one gene. But I have found next information in the "Molecular biology of the cell" by Bruce Alberts: Mycoplasma genitalium: it has only about 480 ...
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133 views

Are all chromosomes equally susceptible to mutation?

The humans have been around for a few million years, other organisms longer yet. Changes that occur in the genome and propagate (may) eventually throw a new species ... or atleast branch off the old ...
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What causes XYY Syndrome?

It's obvious how a misdisjunction can result in klinefelter's syndrome (XXY) but I don't see how this can result in XYY syndrome. Your parents have a collective total of only one Y chromosome so how ...
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What makes a gene dominant or recessive

We all carry two copies of each gene (outside of male sex chromosomes). If the two differ from each other often one is dominant and one recessive. How does this mechanism work on a molecular level? ...
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When can I assume individuals marrying into a pedigree are non-carriers?

If I'm not told that they're non carriers, and if I don't have proof of their geneotype based off of progeny, when can I assume they're non carriers for a trait?
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Hershey and Chase experiment

http://www.youtube.com/watch?v=3QJ4CjFsflA This is a link to Hershey and Chase experiment. According to this experiment, we conclude that DNA is the genetic material. But how do we conclude that DNA ...
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103 views

How do circulating androgens contribute to higher rates of hirsuteness in some women?

I was reading up on ethnic groups in which the women are naturally more hirsute (such as South Asian women) in the context of evolving standards of beauty. I came across this statement on a forum: ...
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318 views

Athletes: nature vs. nurture?

Having watched a lot of olympians the last few weeks, I was struck by how many of them have actually spent their wholes lives/careers training for their one event (be in running a marathon, or ...
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Is the theory of evolution being disproved by bats?

For some species the Darwin's theory evolution makes perfect sense. I can easily imagine how, for example, the giraffe has evolved to its current appearance: the natural selection was favoring ...
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Papers linking telomeres and aging [closed]

I'm currently writing a piece of work about telomeres and aging, and wondered if you could share some good papers you've either read or know of.
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What is the point of being selection-free?

I'm reading "Highly efficient endogenous human gene correction using designed zinc finger nucleases" by Urnov et al. They propose a way to use zinc finger proteins for gene therapy. They repeatedly ...
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46 views

What accounts for size variation in breeds of dogs?

My assumption is that dogs vary so much in size because of artificial selection pressures coming from human breeders, but are there genetic loci that roughly determine approximate size? Do other ...
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How can a three-base codon evolve from a two-base codon?

Inspired by this question among others. It's widely suggested that the current 3-base codon system of encoding protein sequences in DNA evolved from an earlier 2-base codon system. This makes sense ...
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What is the inbreeding coefficient for the female offspring of a sib-mating in a haplodiploid system?

The inbreeding coefficient of a sibling mating for a diploid organism is 0.25 (each allele has a 25% of being identical by descent in the offspring). In haplodiploid organisms, males result from ...
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Are homozygous carriers of the CCR5-Δ32 allele fully immune to all known strains of HIV?

Or is there documented evidence of even one homozygous carrier contracting HIV and staying infected?
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What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?

Apparently all living humans are matrilineal descendants of a single woman who lived 200.000 years ago. She is called Mitochondrial Eve. But at the time she lived there was a different matrilineal ...
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How to map the Gene name to its Gene Symbol?

I am learning in Gene data lately so I apologize for the silly questions in advance. I read a paper for a cancer on human which found some important genes. For example, the paper listed one of genes ...
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1answer
125 views

How does a tiger have stripes?

A vague question, but let me try to explain. My friend explained to me that in females, some cells use one X chromosome, while all others use the other X chromosome. This can result in some ...
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Does the DNA sequence of a butterfly match that of the caterpillar it used to be?

Just had this thought occur to me. If one were to take a DNA sample(or is it RNA?) of a caterpillar before it became a chrysalis, and attempt to match the sample against one taken after the chrysalis ...
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Gene & Protein nomenclature: N-Myc, c-Myc, et. al

Can someone explain (or point me to an explanation of) exactly what is meant by all the different symbols I see used for writing genes and proteins? I think I know that for genes, we use an italic ...
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What are the advantages and disadvantages of using beta-galactosidase compared to luciferase as a reporter gene?

In the University labs, we have used Beta-galactosidase as a reporter gene to quantify the expression initiated by the stress-response promoter in yeast. This was done by exposing one of the two ...
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Do antisense transcripts have different names than their sense strand transcripts?

I want to find which genes in the human genome can potentially be complementary to a transcript that could act as antisense transcript inhibtion? Are cis-NATs (naturally occuring anti-sense ...
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188 views

Would two species of yeast with similar genome sizes have the same number of genes or chromosomes?

Similar organisms generally have similar genome sizes. Given this, would two species of yeast have the same number of genes and chromosomes? Edit: Fixed with thanks to @daniel-standage
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Bicoid regulation of hunchback

I'm learning about development via the example of Drosophila embryogenesis. I understand that bicoid regulates hunchback, among other genes. My question whether the regulation is direct or indirect? ...
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Have there been any experiments that duplicate chromosome copies from 23*2 to 23*3 or 23*4?

Deinococcus radiodurans is an amazing bacterium with a fantastic survival rate. It can survive to high doses of radiation, in a complete vacuum and in hydrochloric acid. How does this bacterium ...
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Difference between mice and rats

What is the actual biological difference between mice and rats? Are they actually the same thing with two different names depending on appearance (are they all mice for instance and we call the larger ...
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Which bacteria have the highest mutation rate?

From my reading on M. tuberculosis, I know that this organism has a pretty high mutation rate due to uncorrected sloppy replication, which leads to a high rate of development of spontaneous resistance ...
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1answer
136 views

What is the difference between xDNA and yDNA?

Wikipedia states that: xDNA contains expanded bases, in which a benzene ring has been added, which may pair with canon bases, resulting in four possible base-pairs (8 bases:xA-T,xT-A,xC-G,xG-C, 16 ...
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Can genetically modified genes jump to bacteria in the eater's intestine?

The Guardian ran an article a while back talking about GM gene's jumping to bacteria in an eater's intestine. Has other research confirmed this phenomenon?
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What do breeders call the effect when a breed resists modification?

It is impossible to breed a blue rose or a cat with a bulldog shape. This is because breeding is limited by gene variations in the population. What do breeders call this effect? UPDATE I guess ...
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What determines testosterone exposure in womb, baby's genetics or mom's body?

I read this article which has the following quote: The ratio between index and ring finger is believed to be linked to exposure to the male hormone testosterone in the womb. And I wonder what ...
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Difference between genetic engineering and synthetic biology

I've recently seen the term synthetic biology being used to describe research involving genetic modification of organisms. What is the difference between synthetic biology and genetic engineering? Is ...
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855 views

What is the smallest number of amino acids required for life?

Is there any hypothesis on the minimum number of amino acids required for life?
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How are Genetic Circuits Modelled?

I've read a recent Nature Methods paper by Moon T.S. et al, in which a synthetic genetic circuit consisting of layered logic gates was created. For example, the paper, a circuit is modelled in Figure ...