Humans have 23 pairs of chromosomes. Each chromosome in pair is homologous to another one in pair.

Does this imply, that the entire chromosome in any cell is obtained from only one parent? I mean entire single chromosome from one parent, and entire homologous one -- from another parent?

This is obviously true for sex chromosomes, especially in boys. They get Y from father and X from mother.

Is similar true for any other pair of chromosomes?

Or they are exchanging genes during mitosis too?

I.e. parents data is distributed grouped by chromosome or by gene?

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    $\begingroup$ See Mitotic Cross-over. I don't know what is the cross-over rate during mitosis though. $\endgroup$
    – Remi.b
    Commented Jun 6, 2016 at 19:23
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    $\begingroup$ To be clear, are you asking specifically about events after fertilization of the egg? Your question about chromosomes obtained "from only one parent" suggests a more basic question of how meiosis works. $\endgroup$
    – Roland
    Commented Jun 7, 2016 at 5:59

2 Answers 2


Yes, each single chromosome came from one parent. However, it is not true that each chromosome came from one grandparent. Due to crossing over in meiosis, the copy of Chr 1 that you got from your father is partially from his father, and partially from his mother. And the same for all the rest of your chromosomes. You will not pass on a whole chromosome as you inherited it onto your children, crossing over will happen in your gametes, so that your kid will get whole chromosomes that are part from your mother, and part from your father. The sex chromosomes are exceptions, because in men, they can't do crossing over, since men have a mismatched pair. (At least in biologically "normal" men.)


No homologous chromosomes do not imply that each cell has genetic information from only one parent.

Let's just talk about one chromosome - and call it Chr1. This chromosome has genes A, B, C, D, and E.

When an egg is fertilized by a sperm, the resulting egg will have a pair of Chr1. One of the Chr1 would have come from the mother (egg) and the other from the father (sperm). These two are a homologous chromosome pair and they both have genes A, B, C, D, and E.

The mother and father contribute different alleles of the genes. So the mother could contribute A.1, B.1, C.1, D.1, and E.1 where as the father could contribute A.2, B.2, C.2, D.2, and E.2.

Then the child has two homologous chromosomes A.1/A.2, B.1/B.2, C.1/C.2, D.1/D.2, and E.1/E.2.

Hope that is a bit more clear.


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