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Homologous chromosomes

Definition

noun, singular: homologous chromosome

(genetics)

A pair of chromosomes having the same gene sequences, each derived from one parent.


Supplement

In a cell, the chromosomes are of two sets: one of which is derived from the mother and the other is from the father. The chromosomes that have the same gene sequences are paired during meiosis. This pairing (called synapsis) happens between chromosomes that are homologous, i.e. chromosomes having the same genes at the same loci but possibly different alleles.

For example, two chromosomes have genes coding for eye color: one may code for brown eyes, the other for blue. One of them may be dominant and the other recessive. Hence, even if an individual has genes for brown eyes and blue eyes, only one eye color is expressed.

A human cell contains 23 pairs of homologous chromosomes: 22 of them are homologous non-sex chromosomes (or autosomes) and 1 homologous pair of sex chromosomes. In females, the homologous sex chromosomes are 2 X’s; in males the X and Y chromosomes.


Compare: sister chromatids.
See also: allele, dominant, recessive.


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genetic

) A diploid cell contains three pairs of homologous chromosomes designated C1 and C2, M1 and M2, and S1 and S2. No crossing over occurs. a. What combination(s) ...

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by lachatausa
Fri Mar 21, 2014 2:55 am
 
Forum: Genetics
Topic: genetic
Replies: 1
Views: 1917

Meiosis prophase I crossover

... (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes.” http://en.wikipedia.org/wiki/Chromosomal_crossover ...

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by gs99
Fri Mar 07, 2014 9:23 pm
 
Forum: Molecular Biology
Topic: Meiosis prophase I crossover
Replies: 0
Views: 2339

Human Gamete Compatibility Going Backwards

on the other hand, although we may have the same number of chromosomes as antelopes, they will be hardly homologous so there will be no cell division

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by JackBean
Mon Jan 06, 2014 10:11 am
 
Forum: Evolution
Topic: Human Gamete Compatibility Going Backwards
Replies: 9
Views: 4388

Regarding pairing of chromosome in karyogram.

Hi. I've tried to match the homologous pairs, but i've stumbled upon a problem. I know it's a trisomy, but the number 15 doesn't match any of the other chromosomes. Can you please help?

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by ebmar
Fri Dec 06, 2013 11:09 pm
 
Forum: Molecular Biology
Topic: Regarding pairing of chromosome in karyogram.
Replies: 3
Views: 1721

Need some help segregation - independent assortment!!!

... a pair of alleles for a particular trait. These alleles are present on homologous chromosomes. Segregation means that these alleles are separated during gamete formation and ...

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by supersapien
Fri Nov 29, 2013 2:36 am
 
Forum: Genetics
Topic: Need some help segregation - independent assortment!!!
Replies: 1
Views: 2483
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