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Questions tagged [sex-chromosome]

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Why are Barr Bodies usually seen along the edge of the nucleus under the light microscope?

We do a typical class exercise of aceto-orsein staining of buccal epithelial cells from female students to visualize Barr bodies under the light microscope. All the illustrations and pictures in the ...
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3answers
155 views

Does sex-chromosomes exist in all the cells in a human body? [closed]

Each cell of a human body contains 46 chromosomes. So every cell must contain a pair of sex-chromosome. Is it true? Then a cell of a male and a cell of a female are always different and never be the ...
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Mitosis of inactivated X chromosome

How is the inactivation of one of the X chromosomes preserved/propagated when the cell replicates? Background: In the XX/XY system of sex determination (i.e. mammals and marsupials), in female ...
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1answer
91 views

Barr body. How does it work? [duplicate]

Barr's body is a spiral X chromosome. If I'm not mistaken, one random chromosome (a healthy woman) is inactivated in each cell. Which X chromosome is inactivated in a given cell is random. I've heard ...
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2answers
119 views

Why is Turner syndrome a problem?

Turner syndrome is a chromosomal disorder where one of the X chromosomes is missing. For more details visit the Wikipedia page I don't understand why missing one X chromosome would be harmful. In ...
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1answer
774 views

Why is there Turner syndrome if one of the X chrosomes is inactivated anyway?

In females one of the two X chromosomes will condensate and turn into Barr bodies. So chromosome abnormality-free women will only have a single transcriptionally-active chromosome. Then why can ...
2
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1answer
84 views

How do the chromosomes arrange themselves after fertilization in humans?

In human reproduction the male produces sperm containing 23 chromosomes and the female has the oovum containing 23 chromosomes , so after fertilization the zygote contains 46 chromosomes. What I want ...
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0answers
152 views

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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60 views

For X-linked recessive diseases, why are only a third of alleles under selection pressure?

My professor wrote the following on one of his lecture slides: For X-linked recessive disease, only a third of the mutant alleles are under selection pressure, so if the disease incidence is stable, ...
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1answer
19 views

Meiosis pairing of chromosomes

How do the X and Y chromosomes synapse during the zygotene stage of when they have almost no homology between them?
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2answers
123 views

What is the X-chromosome responsible for? [closed]

I understand that the X-chromosome is responsible for certain disorders, like red-green colorblindness; but besides disorders, what do the genes on the X-chromosome determine?
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3answers
143 views

What processes regulate the sex of offspring?

It is known that some species are more likely to born male than female (and some maybe vice versa). I understand that it is due to evolutionary perspective (average number of adult males is close to ...
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0answers
58 views

Number of alleles' variations in a mushroom that has over 20,000 sexes

I am trying to understand the mating behavior of a particular species of fungi known as Schizophyllum commune, or the split-gill. I found a blog post that explains the mechanisms that define the ...
6
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1answer
152 views

Why are X-linked illnesses less common in females if females have X-chromosome inactivation anyway?

I have read this post but am still slightly confused about this. Do tissues in the human body not all develop from the same cell(s) in the embryo? If so, I do not see how the cell 'mosaic' would be ...
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1answer
437 views

Sex linked genes?

I am learning about genetics and sex-linked traits. All of the X-linked traits we have considered (eye colour in Drosophila, Duchene Muscular Dystrophy to name a couple)follow the rule that, a female ...
4
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1answer
205 views

Why does the cloned cat, CC, exhibit mosaic fur color?

Since fur color in this cat is from a sex-dependent gene, I see how calico cats occur. However, I don't fully understand why it happens in cloned cats. When the cat is cloned, the DNA is taken from a ...
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1answer
5k views

When was it discovered XY chromosomes decide the sex of a child in humans?

Several stories are told from before-genetic-age (books and movies are my reference, the one present in my mind is Marie-Antoinette by Copola) in which we can always see that women are blamed for ...
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1answer
465 views

Can a Turner syndrome patient develop male characteristics artificially?

From an answer to the question Can stem cells from male convert to cells of female-only organs, and vice versa? Y chromosome is the sex determining chromosome with SRY gene that determines testes ...
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110 views

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 ...
12
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1answer
2k views

Are all Y-chromosomes the same?

Since the Y-chromosome can only pass from male to male child, it would seem to pass intact. Thus, a boy's Y-chromosomes would, I guess, be the same as his father's. Going backwards, would not all men ...
3
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1answer
138 views

Can sexual selection operate in temperature dependent sex determining organisms?

Or more broadly, are distinct forms of genetic inheritance (ie. sex chromosomes) needed for sexual selection? My thinking was that since there are no sex determining loci, there could not be linkage ...
5
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2answers
13k views

Why are the sex chromosomes called X and Y?

Is there a specific reason that the letter Y is used as the symbol for the male chromosome and X is used for the female chromosome?
3
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1answer
147 views

Sex biased gene expression in the X chromosome

It has been shown that the X chromosome is frequently enriched for female biased genes, and has a deficit of male biased genes. For example in this paper, and this one. However, I'm struggling to ...
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1answer
280 views

From a computer science perspective, how is DNA compared for various purposes?

I am very interested in privacy preserving technolgies, such as Microsoft PINQ and would like to see if this is applicable to DNA comparison. Given that I don't have a background in biology, I ...
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1answer
5k views

Crossing white eyed Drosophila with sepia eye

So, I'm doing some drosophila experiments with my high schoolers and I had really poor production of wild type individuals for doing the experiment resulting in not enough to cross with everyone... I ...
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2answers
13k views

What effect does the Barr body have, in relation to female Turner syndrome?

Why do persons with Turner syndrome have developmental abnormalities, when normal XX-females do not, even though they only have 1 active X chromosome? From what I know, one X-chromosome is ...
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2answers
4k views

Do males of all sexual species have Y chromosomes?

I know for instance some cells are sexual, so, this got me wondering, do the males of all species that have distinct sexes have Y chromosomes?
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0answers
121 views

Imperfect dosage compensation

Dosage compensation is used to make up for different copy numbers of the major sex chromosomes in males and females (One X or Z chromosome in one and two in the other). Two main mechanisms of dosage ...
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0answers
250 views

Why is gynodioecy common and androdioecy rare?

Gynodioecy is when a population features individuals that produce both male and female gametes and individuals that produce just female gametes. Androdioecy is when a population features individuals ...
3
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1answer
76 views

Defining dominance and selection in these formulae

This paper uses two equations to explain the different conditions under which sexually antagonistic genetic variance is maintained in a population, while allowing for unequal dominance, for ...
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0answers
52 views

Does unequal dominance mean the X-chromosome should be a coldspot for antagonistic variation?

Sexually antagonistic genetic variation, in a simple model, will persist if the benefit to one sex is (near) equal to the cost in the other, otherwise the polymorphism will be selected out of the ...
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1answer
92 views

Which sex is homogametic in side-blotched lizards?

I'm just trying to find out whether the male side-blotched lizard is the hetero- or homogametic sex in side-blotched lizards (Uta stansburiana) - some reptiles are ZW system (female heterogamete) and ...