Questions tagged [genetics]

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

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Genotype to phenotype map and the G-matrix

Suppose I have a genotype-phenotype map defined by the matrix $\mathbf{Z}$:         The scalars $G,P$ represent the number of genotypes and traits, respectively. ...
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Why and how does complexity usually tend to increase through time?

The question of complexity is classic in the very first lectures of evolutionary biology where the teacher usually tries to tell the students that complexity does not necessarily increase and that ...
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What percentage of the genetic variance is explained by the 'n'- most important loci?

Introduction Standard models in population genetics look up at the evolution of few loci which impact fitness. The variance in fitness is determined by the genetic variance and the environmental ...
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How do mutations of viruses lead to drug resistance?

For instance, after starting zidovudine monotherapy against HIV, resistance develops against the drug because of a point mutation in the RNA transcriptase enzyme to which the drug binds. So how does ...
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What's the aim of genetically modifying of foods/organisms?

On news, articles etc. experts talking about Genetically Modified Foods and Organisms often mentions about their disadvantages like, their potential to harm human health allergies may become more ...
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Is it considered feasible to genetically improve plants for better Carbon dioxide breakdown?

I have found several somewhat related questions and answers here and elsewhere, but I couldn't find, if any scientist groups are researching genetical improvement possibilities of existing plants' ...
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Why would lethal genes evolve?

I've been reading through 'The Selfish Gene' by Dawkins. At a few places in the book he states that incest is damaging because it would give a very high chance of lethal recessive genes becoming ...
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Why do people with type O blood have anti-A and anti-B antibodies?

People with type O blood have anti-A and anti-B antibodies, even without receiving a transfusion. Why?
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Altering the human genome

I recently had a conversation with a rather unusual gentleman who was, let's say, more than a little partial to conspiracy theories. He has this idea that governments are lowering "nanowires" from ...
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Why pick just a single bacterial transformed colony

So after bacteria have been transformed to perhaps grow up a plasmid of interest, why pick only a single bacterial colony from a selective plate for further expansion? I understand that this is to ...
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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 ...
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How is genetic speciation defined?

What determines speciation at a molecular level? At what point does a scientist determine two lineages are different enough to be considered separate species? Does it have a margin of error?
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What if target DNA doesn’t have restriction sites

All the examples on DNA cloning I have encountered have assumed that the target gene and vector both have compatible restriction sites at just the right locations (probably for ease of explanation). ...
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Math behind the Genetic Relationship Matrix

The genetic relationship matrix (GRM) can estimate the genetic relationship between two individuals ($j$ and $k$) over $m$ SNPs and $i$ representing a specific SNP. What I don't understand from their ...
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Is there a genomic code for nucleosome positioning?

What does a genomic code for nucleosome positioning in eukaryotes actually mean? By the code is it right to think that specific DNA sequences favour nucleosomes and others don't? I see that there for ...
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Examples of environmentally influenced gene-expression in humans?

In discussions of the relevant importance of genetic and environmental influences on the development of the individual, it's often stated that the genetic and environmental influences interact. An ...
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Are STOP codons impacted by base insertion or deletion mutation?

I am learning about base insertion and deletion mutations. An example in my textbook is given below. GUU CCA CAU AUC. So if there is an insertion (of guanine): GUU GCC ACA UAU C_ _ (there will be a ...
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Do the eggs for larger litters come from the same meiosis events, or different ones?

There are some species of animals that give birth to more than one pup at a time. In these species, are the fertilized eggs all from one or a limited group of meiosis processes, or are they from ...
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Redundancy of the genetic code

One particular codon codes only for one amino acid, but an amino acid can be coded for by several different codons. Now according to the genetic code, the codon UUU ...
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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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Does the word “polymorphism” refer to the gene, the phenotype, or both?

In genetics, does the word "polymorphism" properly refer to genes, to phenotypes, or both? For example, if there are two alleles that lead to differences in the structure of the D2 neuroreceptor, ...
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Effect of sex-ratio on the effective population size

As stated on this wikipedia article, the effective population size $N_e$ when the sex ratio differs from $\frac{1}{2}$ is $$N_e = \frac{4N_mN_f}{N_m+N_f}$$ I understand the biased sex-ratio ...
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How is it possible for only one in five children to have brown eyes when their parents both have brown eyes?

I have observed that parents having brown eyes had three female offspring with blue eyes, one son with green eyes, while only the youngest daughter had brown eyes. How can they produce so many blue-...
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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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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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How does the colinearity of the HOX genes determine the body plan of an organism?

I was recently reading about colinearity in the HOX genes that give an organism its high-level body plan (where the order of the HOX genes on the chromosome follow the head-to-tail order of body ...
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Why can't we breed watermelons without any remaining seeds in the flesh?

Watermelon is just starting to come in season in the northeastern U.S., and having a seedless watermelon is convenient. The only downside is, the "seedless" almost always still have the immature, ...
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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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Have there been attempts to identify Chomsky's “language mutation” in humans?

I'm not versed in either biology or linguistics so please forgive any naiveties I may commit. I've learned that Noam Chomsky thinks that language is a result of a single genetic mutation in humans. ...
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Why do we still have genetic disorders that show anticipation?

Anticipation whereby symptoms of genetic disorders occur earlier and with more severity as it is passed from one generation to the next. So wouldn't these inherited diseases over a few hundred ...
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How often does bacterial transformation happen?

I have been reading: M. Dröge, A. Pühler, W. Selbitschka, "Horizontal gene transfer among bacteria in terrestrial and aquatic habitats as assessed by microcosm and field studies", Biol. Fertil. ...
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Fisher's Geometric Model for Dummies

Fisher's geometric model is still today one of the most important and fundamental model in evolutionary biology but it seems to me that most student in evolutionary biology don't really understand it (...
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Difference between mutation and DNA damage

What is the strict difference between mutation and DNA damage? As far as I understand it, a mutation is an alteration in the genetic sequence, having "tricked" the repairing machinery and thus ...
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What is the difference between copy number changes with and without allelic imbalance?

I require some clarification on copy number aberrations (structural gain and loss in chromosomes). From what I understand, gain/loss per se can be divided into two types. Consider two alleles, A and ...
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What determines the colors and patterns of a clam shell?

Earlier this week I was looking at some bivalve shells that had ornate patterns which ranged in color from a light orange-pink to a deep orange-red. Here is an image I found online that seems to be of ...
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How was the cama's life expectancy computed?

A cama is a hybrid between a male dromedary camel and a female llama. The first cama was born on January 14, 1998, yet on the Wikipedia page it is said that a cama's life span is 30–40 years. How was ...
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How do I read a sequence logo?

I'm looking at a paper that uses several sequence logos to illustrate the consensus sequence of certain sites. Here is the most important of the sequence logos I'm interested in: The explanations I ...
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Can an organism obtaining a part of its genome via horizontal gene transfer be called a “hybrid”?

Wikipedia definition of "hybrid" offers many competing definitions. But most seem to be centered on sexual-reproduction gene transfer. Is there an official (in a textbook or widely accepted peer ...
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Why babies cry after they are born?

Well I have noticed that almost all of the babies cry after birth, but some of them (1 to 1,000,000? births) don't cry. So, we have: Why is this happening (the cry after birth)? Also why animals ...
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Why does the proportion of transposable elements vary so much across species?

Intuitively, transposable elements (TEs) are harmful as they may cause genome instability. However, some people argue that TEs are also sources of variations, especially regulatory sequences[1]. If ...
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Horizontal gene transfer from humans

It is known that some viruses embed themselves in the human genome. Is there a mechanism by which human genes can be transferred to other animals or plants by means of viruses shuttling them from ...
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How is the exogenous DNA protected from degradation during bacterial transformation?

During transformation, a bacterium can take up DNA from its environment. A small fraction of bacterial species are known to be naturally competent, meaning that they can engage in this sort of ...
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Why are adenoviral vector vaccines safe in terms of insertion mutagenesis due to genome integration and E4 region's proteins effects?

Disclaimer: I'm neither a genetics professional nor an anti-vax fanatic, I just tried to compare COVID-19 vaccine types currently available on the market and got some questions that I'd like to answer ...
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Is the number of legs in myriapoda determined entirely by the genome?

Myriapoda (comprising, among others, millipedes and centipedes) can have hundreds of legs (Illacme plenipes having up to 750 legs). Interestingly, the number of legs (or leg pairs) appears to differ ...
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Genetic expression in interspecific hybrids

Referring to interspecific hybrids, I have the following two questions:- Quoting from wikipedia:- The offspring of an interspecific cross are very often sterile; thus, hybrid sterility prevents ...
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Why is polyploidy much more common in plants than in animals? [duplicate]

There are very few animals with polyploidy like salamanders. Why is it that polyploidy is so uncommon in animals? On the other hand there are numerous examples of polyploid plants. If ut something to ...
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Why is the strength of genetic drift inversely proportional to the population size?

I saw a concept on the Internet that says "the strength of genetic drift is inversely proportional to the population size". I don't know why they are inversely proportional? Can somebody explain? ...
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What is the instructional language of DNA?

DNA carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms and many viruses (Wikipedia). Is it already know how ATCG's sequences ...
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Is it possible for a child to grow taller than their tallest parent?

I have heard that offspring can't grow taller than either of their parents but I've also heard that sometimes some gene activation can skip generations. Is it possible for a child to grow taller than ...
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What are the function(s) of Alu elements in the cell?

My 2008 biology book (1) states that some 10% of the human genome consists of relatively short (~300 nucleotides long) Alu elements which do not code for proteins but many of which are transcribed ...

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