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Questions tagged [chromosome]

A single piece of DNA coiled and organized along with RNA and proteins found in the cell.

34 questions with no upvoted or accepted answers
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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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What would the resulting karyotype be if someone with Klinefelter syndrome fertilized an “empty” egg?

Endoreduplication: is a form of nuclear polyploidization that results in multiple, uniform copies of chromosomes. This process is common in plants and animals, especially in tissues with high ...
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Offspring of parents with different number of chromosomes

Many papers report that dog-whelks (Nucella lapillus) show a distinct chromosomal polymorphism between populations of 2n = 24 up to 2n = 36. Could somebody please tell me how many chromosomes the F1 ...
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Why does cell waste energy in meiosis, between meiosis 1&2

As far as I have learnt about meiosis I have read that anaphase 1 is followed by telophase 2 where chromosomes change back to reticulum.but in the very next stage i.e prophase 2 they again start ...
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Is there a defined non-trivial chromosome number distribution for a given kingdom?

I'm pretty aware of the mechanisms for chromosome number evolution in specific groups (e.g. inside a given genus). Nevertheless, looking at a broader scale (e.g. in the Metazoa kingdom), is there a ...
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Can cancerous cells reach the Hayflick limit?

This may be a stupid question, but I've been wondering. Each time a cell divides, the telomeres on the chromosomes shorten. If this goes on for long enough, the chromosomes will no longer have ...
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Why are published chromosome counts for polyploids often incorrect by an integer multiplication factor of the original diploid like count?

Why are published chromosome counts (done using techniques such as root smashes) for polyploidy flowering plants often incorrect by a multiplication factor of 2 or 3 from the original diploid like ...
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examples of chromosomal aberrations with lack of sexual chromosomes?

Are there any examples in animals where individuals survive having no copies of their sexual chromosomes?
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Example(s) of reduced rate of mitotic progression?

Most species complete mitosis, and in particular the process of chromosome condensation, rather quickly, in a matter of minutes. Are there any known species that undergo mitoses with substantially ...
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Are there any mammals in which polyspermy produces viable zygotes?

Are there any mammals in which polyspermy produces viable zygotes? In the wikipedia page it is mentioned that there is a delicate equilibrium between female defenses against many sperms, which ...
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chromosome 19 and recombination

Im doing a project with structural variation created by recombination within the human genome during spermatogenesis, where im especially examining intrachromatid homolog recombination. I find that ...
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Number of DNA strands per chromosome

As I was reading Griffith's Introduction to genetic analysis this evidence was provided for single DNA makes single chromosome. Eventually geneticists demonstrated directly that certain chromosomes ...
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Why more than one chromosome in an organism?

Why not one chromosome to house genome in organisms but multiple? Is it for epigenomic purposes?
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Did the chromosomal fusion within humans affect phenotypical change compared to the separated chromosomes in the other apes?

I just read this article on the evolutionary divergence between humans and chimps, and how the most significant event was when the 24 number of chromosomes in chimps was reduced to 23 in humans due to ...
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What is(are) the mechanism(s) that stop cells from fusing in vivo?

I just learned about the phenomenon of 'cell fusion' in which two diploid somatic cells can combine into some aneuploid cell in vitro and proceed to proliferate in culture. Apparently this can even ...
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Coefficient of relatedness for a locus on the Z chromosome

So i know that the ZW determination system is the equivalent for XY in birds. Moreover, I know that the coefficient of relatedness between siblings for the X chromosome is 0.5 so im guessing that the ...
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Is there any technique can quickly expand one set of cell chromosomes?

Assume a cell type is very scarce while isolated out and hard to expand in vitro, and I wanna have more of its chromosomes, is there any technique , in vivo or in vitro or ex vitro, any would count, ...
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What is the 'fallacy' in simple segregation rules in reference to polyploidy?

I was reading a paper Why polyploidy is rarer in animals than in plants’: myths and mechanisms, Mable 2004 where I found this sentence. Stebbins (1950) suggested that autopolyploids were probably ...
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How did researchers find out that it was only the maternal chromosome that underwent deletion in Angelman syndrome?

It is known that in Angelman syndrome, the chromosome 15 undergoes deletion in the maternal chromosome while in Prader-Willi it's in the paternal. I understand it can be detected by FISH or other ...
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How do we know Denisovans had 46 Chromosomes

What allows sequencers to conclude that Denisovans had 46 chromosomes rather than merely knowing Denisovans had the crossover material arranged in 48 or say 44 chromosomes? See http://genetics....
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How to engineer chromosomal duplications?

Specific genetic engineering of chromosomal aberrations like deletions, inversions and translocations are doable by using the CRISPR/Cas system or the other programmable nuclease systems. Insertions ...
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Evolution of sexually concordant genetic variation on the X-chromosome

It was theorised in 1984 that sexually antagonistic genetic (SA) variation should more easily evolve on the X-chromosome. This is partly because female beneficial/male deleterious mutations face less ...
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Is it possible to assemble chromosomes from different parent cells?

Assuming that one or two parents are carrying a genetic defect/disease which is localised on a specific chromosome, would it be possible to assemble a new haploid cells taking a (half) chromosome from ...
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Are human cells tetraploid during cell division?

If human cells are diploid, and DNA replicates before cell division, does it mean that our cells are tetrapolid for a short period of time (DNA replication - cell division). Photos of chromosomes are ...
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31 views

How did the molecular machinery for recombination originate?

I'm wondering about the origins of genetic recombination. During crossover new chromosomes are created. They have different allele combinations from the original two chromosomes. This process allows ...
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Factors affecting which chromosome will come from the father

Tell me please. In course of biology, I remember that a man has XY chromosomes, and a woman has only X. Accordingly, depending on which chromosome comes from Father(man) Y or X, a girl (XX) or a boy (...
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Question about aneuploidy

I am learning about aneuploidy and non-disjunction and just wanted some clarification with regards to terminology. In particular, do the terms monosimony and trisimony refer only to INDIVIDUALS (i.e. ...
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Calculating gene separation -a genetics problem

I am really struggling with genetics. In particular, I have the following question Now I am OK with calculating the separation of genes in centrimorgans when I have data like so: But in the first ...
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Mitotic chromosome condensation screen

If I want to screen for mutant yeast (S. cerevisiae) colonies that have defects in mitotic chromosome condensation, can I screen for colonies arrested in Mid-M phase? Would that work?
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Differing Flow Cytometry Genome Sizes and Sexual Mating Implies Differing Chromosome Counts

Do the fundamental principles of genetics strongly suggest the following is a derived conjecture? If 2 flowering plant species A and B have widely differing genome size (at a minimum a 50% difference)...
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Barr body Giemsa staining

Not all the female cheek cells show Barr Bodies when stained with Giemsa stain? Only 30 to 40% female cells show Barr Bodies. Why? Our Experiment: We washed mouth twice with listerine to reduce ...
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Identify which of the two columns A and B represent gene and chromosome

I am a bit confused on this question in my Textbook (STD 12) and have got all sorts of answers on searching it but I am still not able to comprehend it literally. Can someone answer this and explain ...
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6k views

Behaviour of chromosomes and genes

I recently read a comparison between behaviour of chromosomes and genes - which had two statements understated - Independent pairs segregate independently of each other One pair segregates ...
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7k views

Unsure about definition of “n” and “C” values in mitosis

I am preparing for a Biology exam and I'm reviewing the "n" and "C" notation used in mitosis. My professor said that when the cell replicates its DNA in S phase of mitosis, we get twice the "amount" (...