Questions tagged [chromosome]
A single piece of DNA coiled and organized along with RNA and proteins found in the cell.
237
questions
0
votes
1answer
89 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 ...
0
votes
0answers
25 views
What's the difference (functionally speaking) between yeast centromeric plasmids and artificial chromosomes?
Historically, yeast artificial chromosomes (YACs) have been used for genome sequencing projects in the late 1990's. Nowadays, most researchers seem to use centromeric plasmids for expressing ...
0
votes
0answers
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 ...
0
votes
1answer
37 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 ...
0
votes
0answers
13 views
What is the mechanism of chiasmata terminalisation in meiotic prophase I?
There's barely any fresh literature available about how the chiasmata between the non sister cromatids of homologous chromosomes separate.
I'm curious to know about the forces responsible for pulling ...
1
vote
1answer
42 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 ...
0
votes
1answer
27 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
2answers
107 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 ...
1
vote
1answer
83 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 ...
2
votes
0answers
33 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 ...
2
votes
1answer
86 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 ...
4
votes
1answer
89 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 ...
-1
votes
1answer
45 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 ...
3
votes
1answer
168 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 ...
0
votes
0answers
11 views
How do chromosome count differences produce viable offspring during speciation in animals with sexual reproduction
So, many closely related animals have different chromosome counts.
It would seem that most chromosome count differences lead to sterile offspring. Further, it would appear that gametes with ...
0
votes
0answers
27 views
Why/ how sister chromatids stay together after replication?
As we know, in mitosis, after S phase each linear DNA molecule (associated with 1 chromatid), get doubled. These sister chromatids, in prophase and metaphase; are joined with a common centromeric ...
9
votes
1answer
105 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 ...
0
votes
0answers
26 views
how many crossing over sections are in human dna?
i have found in wikipedia:
At a given chiasma, an exchange of genetic material can occur between
both chromatids, what is called a chromosomal crossover, ...
In humans, there seems to be one ...
1
vote
2answers
226 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 ...
-1
votes
2answers
2k views
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 ...
1
vote
0answers
29 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 ...
0
votes
1answer
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
1answer
53 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 ...
21
votes
2answers
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 ...
0
votes
1answer
85 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,...
-4
votes
1answer
54 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?
0
votes
0answers
105 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 ...
2
votes
0answers
49 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 ...
0
votes
1answer
99 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 ...
1
vote
1answer
118 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
0answers
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 ...
1
vote
2answers
91 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 ...
-1
votes
1answer
184 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).
...
2
votes
1answer
277 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. ...
5
votes
1answer
113 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 ...
1
vote
0answers
50 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?
3
votes
0answers
54 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
1answer
41 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 ...
0
votes
2answers
107 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.
2
votes
1answer
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 ...
1
vote
1answer
1k 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 ...
3
votes
2answers
762 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 ...
0
votes
2answers
102 views
What is the chance a given gene will end up in a given gamete?
Let us say a germ cell had a desired allele. This germ cell was replicated during interphase so that it had two of the desired allele. It then underwent meiosis.
My question then is, what is the ...
0
votes
1answer
65 views
Are there chromosomes that we inherit that are not recombinated? [closed]
We do have chromosomes that recombinated ,but aren't there pure chromosomes that are not recombinated that people would have?
2
votes
2answers
159 views
Is there any system how genes are spread across chromosomes?
Every chromosome being a wrapped DNA molecule contains thousands or more genes.
Now, is there any system why a gene A goes to a chromosome K and gene B to chromosome J?
1
vote
1answer
210 views
With over 400 chromosomes, does mitosis in a species of butterfly happen in the same way as in humans?
The beginning of the Ars Technica article Gene editing crunches an organism’s genome into single, giant DNA molecule begins:
Complex organisms have complex genomes. While bacteria and archaea keep ...
2
votes
1answer
129 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 ...
1
vote
0answers
31 views
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 ...
0
votes
1answer
50 views
Human genome, chromosomes
I have a very basic question, but it seems the hardest to me.
So we have 46 chromosomes (23, 2 copies of each). Do all chromosomes have the same DNA? If so, does it mean that in different cells with ...
0
votes
1answer
87 views
What exactly happens during the crossover [closed]
My knowledge of biology is rather limited, but I think I have a grasp of some basic concepts. For me (as a person close to math) a chromosome is a sequence of elements from the set {A,C,T,G} of some (...
