Questions tagged [chromosome]
A single piece of DNA coiled and organized along with RNA and proteins found in the cell.
245
questions
1
vote
0
answers
32
views
The numbers of chromosomes during Meiosis [duplicate]
There is something about the numbers of chromosomes that doesn't make sense to me:
Let's take this illustration:
So a gamete has 23 chromosomes, which are haploid (have only one chromatid), is that ...
- 139
2
votes
0
answers
32
views
What is the DNA sequences between two Inverted Repeats called?
I would like to know some rules about the nomenclature of Inverted Repeats DNA sequences. More in detail, I want to know what is the name of sequences between two inverted repeats.
For example, I have ...
- 21
8
votes
0
answers
91
views
How much is known about dinosaur DNA condensation and crosslinking?
The conclusion section of Bailleul et al. (2020) Evidence of proteins, chromosomes and chemical markers of DNA in exceptionally preserved dinosaur cartilage is:
The identification of chemical markers ...
- 4,907
0
votes
0
answers
23
views
Do homologous chromosomes have same rates of gene expression in a cell?
I was googling around and found only articles related to XY differences in expression. Can you please clarify if homologous genes/chromosomes have about the same levels of expression in a cell or one ...
- 101
0
votes
1
answer
119
views
Could someone explain how chromosomes are counted here?
I'm not sure how chromosomes are counted in this picture. I would reason that there would be 8 chromosomes in the diploid cell, but that doesn't seem to be the case. Could someone explain?
- 21
1
vote
1
answer
57
views
How is it determined whether a chromosome is maternal or paternal for imprinting?
For imprinting, how does the cell determine which chromosome is maternal and which is paternal? For example, in the parental imprinting of insulin-like growth factor 2 (Igf2) on chr7 (autosome), how ...
-1
votes
2
answers
83
views
Are the complementary base pairs known as genes? [closed]
In my text book ,it is written that a chromosome has 1000s of genes and it is distributed throughout the chromatids except in the centromere. But we know that the chromosomes have DNAs inside them ...
- 196
0
votes
0
answers
75
views
Why do chromosome pairs have different shapes and sizes?
When I look at microscopic images of human chromosome pairs I see that they have different shapes and sizes.
Is there a deeper biological reason for that? Is there some evolutionary pressure for them ...
- 9
-1
votes
2
answers
53
views
Chromosomal disorders
I was reading about chromosomal disorders and encountered a line stating that
'An individual may lack one of any one pair of chromosomes'
So does it mean that an individual cannot have monosomy of ...
-1
votes
1
answer
62
views
Is MPseq more cost effective than FISH when looking for chromosomal abberations?
There are some papers out there that propose to use MPseq in addition to or instead of FISH when looking for chromosomal aberations in the context of cancer
e.g. this one on infiltrating lobular ...
- 294
0
votes
0
answers
62
views
Do all stem cells have a full number of chromosomes?
Do all or only some stem cells have a full number of chromosomes?
- 81
1
vote
1
answer
161
views
What is prochromosome?
My textbook says that prochromosome is a false chromosome present in the nucleoid of prokaryotes.
I looked up Wikipedia and all over internet and this word is kinda sus. So I'm asking about it here. ...
- 141
0
votes
1
answer
106
views
How many genes per 23 chromosomes in human genome? [closed]
It is estimated that humans have between 20,000 and 25,000 genes. Every person has two copies of each gene, one inherited from each parent.
There are 46 chromosomes, half from the mother, half from ...
- 305
-2
votes
1
answer
54
views
How could a cell only have chromosomes from father or from mother? [closed]
How could arrangement one even be possible? How could a cell only have chromosomes from father or from mother?
[Image modified from "The laws of inheritance: Figure 5," by OpenStax College, ...
0
votes
1
answer
171
views
When the sister chromatids are joined in the centromere, why is it stated that the number of chromosomes is 46 and not 72?
Before the DNA is replicated in a human somatic cell, the cell has 46 chromosomes. Also, after the sister chromatids are separated during Anaphase, the chromosome number in the cell doubles to 72, so ...
- 105
0
votes
0
answers
30
views
What is the structure of heterochromatin?
A short article about euchromatin and heterochromatin mentions that the structure of heterochromatin usually depicted in images "has never been visualized in vivo, and its existence is ...
- 135
0
votes
1
answer
56
views
What is a proximal deletion breakpoint?
I am reading a journal paper about the relationship between NCAM2 and autism. I have come across the following statement in the paper:
Based on analysis utilizing the UCSC Genome Browser (hg18, build ...
- 1,561
1
vote
1
answer
156
views
Do prokaryotic chromosomes have centromeres?
I found this here.
Eukaryotic chromosomes are always linear. ... In contrast, prokaryotic chromosomes are either completely devoid of centromeres or carry the so-called “plasmid centromeres” which ...
- 255
0
votes
1
answer
36
views
Do we come to know which allele is dominant by seeing family genration tree only?
I know that a Gene has Alleles (variation) and one is Dominant over Other i.e the Other Recessive.
Then I got a Thought that How can we tell whether an Allele is Dominant or Recessive...... and I came ...
0
votes
2
answers
132
views
What exactly is "chromosome topology"?
I've been reading a lot about Hi-C lately, and this has been bothering me. So far as I can tell from reading around, the topology is related to the conformation of the linear chromosome. This seems ...
- 35
3
votes
1
answer
125
views
Recombination Data Set
So I was looking over some genetics question and came across this data set.
In Fruit fly Drosophila melanogaster, there is a dominant gene b+ for grey body color and another dominant gene c+ for ...
- 39
2
votes
0
answers
39
views
Shrinking size of Y chromosomes
I read on the web that the size of Y chromosomes decreased in earlier period of time and the picture below tells that it is still occurring.
So basically I want to know what caused this shrinking and ...
- 221
2
votes
1
answer
95
views
How can we determine which chromosome came from which parent? [closed]
In this article there is a graph (figure 1) describing different levels of methylation in the maternal and paternal chromosomes after karyogamy.
How can the researchers identify which chromosome ...
- 943
6
votes
1
answer
116
views
Why are Chromosome Territories important?
Chromosomes occupy discrete regions of the nucleus, referred to as 'Chromosome Territories'. This spatial organization is emerging as a crucial aspect of gene regulation and genome stability in health ...
- 705
-1
votes
1
answer
100
views
Why do some karyotype graphs contain 46 pairs of chromosomes?
The human genome consists of 23 pairs of chromosomes. Two copies of each pair connect to each other at the centromere. Normal karyotype graphs should look like this:
But some karyotype graphs contain ...
- 167
3
votes
1
answer
420
views
Does DNA being circular or linear directly affect the speed of DNA replication?
Let's say we have two DNA molecules of equal length, one belonging to a prokaryote and the other to an eukaryote. It's known that replication of the eukaryotic DNA is faster in this case. One clear ...
- 33
9
votes
1
answer
139
views
What causes cells to inactivate one X-chromosome?
Normally, when a cell has two X-chromosomes (female genome), one is randomly inactivated. How does the cell detect that there are two X-chromosomes in the first place?
Is there some kind of protein ...
- 642
0
votes
2
answers
824
views
Why do chromosomes uncoil back to chromatin after cell divisions?
At the telophase of meiotic and mitotic cell divisions, the chromosomes of daughter cells uncoil back to chromatin, but after interphase, it coils up again to form visible chromosomes. Why do this ...
- 33
1
vote
0
answers
32
views
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 ...
- 51
0
votes
1
answer
33
views
Chromosome size without heterochromatin
Im doing different analysis of the human chromosomes and diffent loci, however when using different databases, the heterochromatin structures are not part of the human genomes. I know that ...
4
votes
1
answer
68
views
Chromosome naming convention: Why are there chromosomes named "1" and "1A"?
I've been stumbling on multiple genome of birds where there is a "1A" chromosome and a "1" chromosome. For example, the zebra finch has 1A and 4A. What does that mean?
Do you have any resource about ...
- 796
21
votes
2
answers
4k
views
Why is Chromosome 1 called Chromosome 1?
Chromosome 1 is the designation for the largest human chromosome. Humans have two copies of chromosome 1, as they do with all of the autosomes, which are the non-sex chromosomes. Chromosome 1 spans ...
- 341
0
votes
1
answer
111
views
What is the Definition of Homologous Chromosomes? length, gene position are the same or similar? [duplicate]
what is the Definition of Homologous Chromosomes?
this post says
Homologous chromosomes are chromosome pairs (one from each parent)
that are similar in length,...
- 341
-4
votes
1
answer
72
views
In a Chromosome, 2 nm is the length of what?
this figure comes from the nature
2 nm at the top right hand corner is the length of what?
- 99
0
votes
0
answers
125
views
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 ...
- 81
2
votes
0
answers
103
views
My understanding of chromosomes and the processes related to them is lacking [closed]
I'm sorry for the incredibly simple question, I just can't seem to find any answers elsewhere online.
I am a high school student currently studying for the upcoming AP biology exam, and recently I ...
- 29
0
votes
1
answer
155
views
Possible combinations in the Meiosis' Telophase 1
As you might already know
Meiosis is the process in eukaryotic, sexually-reproducing animals that reduces the number of chromosomes in a cell before reproduction $^{[1]}$
One of the reasons why ...
- 103
1
vote
1
answer
241
views
Barr body in mitosis
In early embryonic development, some female cells pass through a process called lionization and one of the X chromosomes get condensed and began to be called Barr body.
What I don't understand is ...
0
votes
0
answers
32
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 ...
1
vote
2
answers
132
views
Is it possible for a sex chromosome to be homologous?
I am following a great introductory biology course online, MITx: 7.00x on edX.
A question in the course assumes a cross between a pure-breeding male fly and a pure-breeding female fly:
You are ...
- 123
-1
votes
1
answer
491
views
The organisms of the same species with a different number of chromosomes [closed]
I am looking for some specific creatures. The organisms of the same species that have different chromosome numbers. Just like male grasshopper (23 chromosomes) and female grasshopper (24 chromosomes).
...
- 255
2
votes
1
answer
442
views
Is there random assortment in metaphase II?
First, a little notation. Call a the first chromosome from my mother and A its homologous partner from my father. ...
- 23
5
votes
1
answer
148
views
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 ...
- 151
1
vote
0
answers
56
views
Why more than one chromosome in an organism?
Why not one chromosome to house genome in organisms but multiple?
Is it for epigenomic purposes?
- 104
3
votes
0
answers
57
views
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 ...
-2
votes
1
answer
47
views
Do we know which traits reside in which chromosome? If not, how about the next 10 years? [closed]
Assuming we develop a technology that allows us to make human gametes (sperm & eggs) combining chromosomes from different persons. Thus we take 1st chromosome from 1st person, 2nd chromosome from ...
- 1
0
votes
2
answers
122
views
How much shorter is the short arm of a chromosome? And why?
I keep reading that the p arm is shorter than the q arm. But I cannot find an explanation of how much shorter nor an explanation for the difference.
- 101
2
votes
1
answer
1k
views
What is an "end-to-end fusion" in the context of telomerase? [closed]
Telomerase is said to prevent "end-to-end fusion" of chromosomes.
My question is threefold:
What is an "end-to-end fusion"?
How does Telomerase prevent end-to-end fusions?
Why do end-to-end ...
- 43
1
vote
1
answer
2k
views
Do chromosomes line up as pairs in mitosis or meiosis?
Here is a question from the book SAT II Success Biology E/M (where the SAT is the exam taken by the American high school students):
Homologous chromosomes line up in pairs in
(A) metaphase of ...
- 297
3
votes
2
answers
997
views
What is a chromosome?
I read the wikipedia article and am confused if a chromosome is the pair of two chromotoids or if each chromatoid is considered a chromosome.
I've heard someone say we have 23 pairs of chromosomes ...
