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Questions tagged [cytogenetics]

A branch of genetics that is concerned with the study of the structure and function of the cell, especially the chromosomes.

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Why may some telomeres not appear on metaphase chromosomes using Q-FISH?

There are some chromosomes that appear to have missing telomeres e.g. 2 instead of the expected 4, but there appears to be no fusions or breaks.
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Gene expression system

What is the mechanism of action of Gal4-UAS expression system in Yeast and it's application in Drosophila ? I want to know the steps by which the Gal4-UAS expression system is able to over express or ...
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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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Does aneuploidy include the loss of chromosome arms?

I'm wondering if the definition of aneuploidy includes loss of a chromosome arm (telosomy) or arms (ditelosomy). I'm aware that aneuploidy normally depends on the number of discrete chromosomes (so a ...
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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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What tools are used in animal cloning?

So I was reading up on articles to do a project about cloning but there were no places in the article where It states the tool used to take the gene out of the nucleus and insert it into plasmids ? ...
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How can a chromosome translocation in somatic cells lead to disease?

Looking at this picture... http://ghr.nlm.nih.gov/handbook/illustrations/balancedtranslocation.jpg ...I get the impression that the part of chromosome is attached to other chromosome, but it is not ...
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Explanation about cytogenetic notation

What is the correct meaning of cytogenetic notation "inv(4)(p13q22)" ? Inversions at chromosome 4, at the p arm 13 is inverted AND at q arm 22 is inverted OR Inversions at chromosome 4, the p13 ...
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What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material (Big genome size)? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and energy)?...
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Lyonization and X-linked disorders?

Lyonization or X-chromosome inactivation is the conversion of all but one, X-chromosomes in Females into non-coding heterochromatin (i.e. deactivated) leading to the formation of one or more Barr ...
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Is there a realtime molecular clock within the genome to co-ordinate the developmental sequences in an embryo?

It is difficult to assume that the massive number of co-ordinated developmental sequences in a developing embryo is controlled by molecular signalling alone. Is anyone aware of a molecular or ...
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Why are certain aneuploidies more common?

Certain aneuploidies such as trisomy-21 (Downs syndrome), trisomy-18 (Edward syndrome), Turner syndrome (XO) etc are more common than others. I had a vague thought that it is related to chromosome ...
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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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Number of spindle fibres during Metaphase?

During metaphase, the chromosomes are arranged on the equatorial plate and are attached to spindle fibres. After S phase, can the cell be said to attain the configuration of 4n? Also, during ...
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Evolutionarily speaking, why do humans have 46 chromosomes

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Monkeys, chimpanzees, and Apes have 24 pairs (twenty-four pairs), for a total of 48. What caused humans to have 46? ...
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1answer
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Is ovum + ovum fertilization possible for human?

In humans is it possible to fertilize a ovum with another ovum from the same female subject? I already found some works in which the ovum is fertilized by a somatic cell (see e.g. this ), but I am ...
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How does one measure the length of telomeres?

My questions are: What techniques are available for doing so? Are they destructive ? What is their accuracy ?
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Finding the number of chromosomes of an organism

For a school project I need to find the number of chromosomes of an organism (specifically the adelie penguin, Pygoscelis adeliae). After several internet searches and a look through the encyclopedia ...
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X chromosome “weight”?

According to Wikipedia, the X chromosome has approximately 153 million base pairs, while the Y chromosome has only 60 million base pairs. Thus, the difference is roughly 93 million base pairs. My ...