Questions tagged [chromosome]

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

Filter by
Sorted by
Tagged with
0
votes
1answer
26 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
41 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
61 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
35 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
53 views

Who introduced the number of chromosomes equation e.g. 2n = 4x = 52?

Strassburger introduced the terms haploid and diploid to mean having a single, or a double number of chromosomes. When and by whom was x introduced to mean the basic number of chromosomes, and n to ...
1
vote
0answers
81 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
26 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
53 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
37 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
79 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
58 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
113 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
0answers
63 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
48 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?
0
votes
0answers
21 views

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 (...
3
votes
0answers
42 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
37 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
96 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
539 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
469 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 ...
1
vote
2answers
424 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 ...
1
vote
2answers
72 views

What is the chance a given gene will end up in a given gamete?

Let us say a somatic cell had a desired gene. This somatic cell was replicated during interphase so that it had two of the desired gene. It then underwent meiosis. My question then is, what is the ...
1
vote
1answer
60 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
106 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
167 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
95 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
29 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
44 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
84 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 (...
1
vote
1answer
449 views

Genotypes of gametes produced by an F1 individual?

I have an urgent question as I have an exam tomorrow. I was skimming some past exam papers and one question came up which has me completely confused. A cross was made between a pure breeding ...
2
votes
2answers
254 views

Why the genome is divided into several chromosomes and not just a single big chromosome?

In many eukaryote species, there are several chromosomes. In humans, for example, there are 23 pairs of chromosomes. Why are there several chromosomes and not just a join of all chromosomes into a ...
1
vote
1answer
38 views

On what basis is each chromosome given a number? [duplicate]

On what basis is each chromosome given a number? There appears to me to be no visible ordering between each pair. Is there any reason other than differentiation?
0
votes
1answer
40 views

How does the number of chromosomes evolve through generations? [duplicate]

Mitosis is a complex mechanism that, through mutations and crossover, determines how a chromosome is composed. But at that point, the number of chromosomes is already determined: how can this number ...
1
vote
0answers
30 views

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 ...
1
vote
0answers
159 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 ...
0
votes
1answer
127 views

Are the sister chromatids exactly the same?

I'm having doubts about whether the sister chromatids are exactly the same or not. I know that they are the arms that carry the information genes (the alleles), but I don't know if they are exactly ...
2
votes
1answer
53 views

V(D)J recombination on homologous chromosome

V(D)J recombination is known to recombine IG locus of a B cell. Is anything known about how the recombinations on two homologous chromosomes are connected? For example, are the selected V(D)J couples(...
1
vote
1answer
99 views

What is linkage?

If two genes are on the same chromosome, are they always “linked”? What if they are more than 50 cM apart? Then they would follow Mendalian pattern of inheritence. So are they still linked?
3
votes
2answers
145 views

Human ancestor reproduction after chromosome fusion

I read somewhere that human chromosome 2 is the result of 2 primate chromosomes fusing together somewhere along our evolutionary journey. This is why we have 23 chromosomes while other primates have ...
3
votes
2answers
563 views

Do chromosomes change with time?

An offspring is 23 chromosomes of mother and 23 of father, if one of the mate learns say music after the birth of their first child— will their second offspring have better music skills than former? ...
3
votes
0answers
23 views

Why can plants handle extra chromosomes much better than animals? [duplicate]

Why can plants handle being polyploid way better than animals, where it is almost always fatal? I found a 2004 paper while searching about this topic, but I'm wondering if there have been any recent ...
0
votes
2answers
137 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?
2
votes
2answers
416 views

What are the total number of alleles for a single trait?

Humans receive a copy of gene from both parents and each gene has an alternative form called allele. Does every person possess two genes and four alleles for a single trait?
0
votes
1answer
987 views

Does incomplete dominance follow or not follow the law of segregation?

The law of segregation says that in hetrozygotes, dominant and recessive alleles remain together without mixing into one another. In incomplete dominance, two alleles blend with each other, and the ...
-2
votes
1answer
88 views

what is the difference between gene and allele? [closed]

I want to know about gene and allele As we know allele is pair of genes they are ;present on only one chromosome or on homologous chromosomes? Or its like that;one chromosome has only one gene out of ...
0
votes
2answers
495 views

Is a microspore diploid?

In gymnosperms the plant body is predominantly sporophytic. It produces microspores or megaspores my textbook says that these undergo reduction division in order to form male gametophytes pollen ...
17
votes
5answers
5k views

Are there examples of cells with more than one nucleus?

I've always wondered why cells have only one nucleus, as having multiple would seemingly prevent mutation. Are there examples of organisms with multiple nucleuses? If not, is there a reason?
0
votes
1answer
843 views

Don't understand how multiple replication bubbles work

I'm not exactly sure how multiple replication bubbles work, assuming were working with a linear, eukaryotic chromosome. This is a diagram for reference: It appears that the DNA is being synthesized "...