0
$\begingroup$

For example, zygote had abnormal number of chromosome (45, 47, 48 etc) or corrupted chromosome. And fetus was born. Then it means that in any cell of newborn's body there will be the same not normal or corrupted amount of chromosome?

$\endgroup$
0

2 Answers 2

1
$\begingroup$

The terms 'corrupted chromosome' and 'corrupted zygote' are very unusual and quite loaded. Mutations occur all the time (of the order of 1-10 mutations per individual per generation in humans, Drake et al. 1998) and it is unclear how big a mutation needs to be so that you talk about "corruption".

But in any case, yes, the egg will copy itself via mitosis to create the whole body. As such any mutation (whether a small substitution or a chromosomal duplication) present in the egg will be transmitted to all the daughter cells and will therefore be found in the entire body. Note that many of the changes in chromosome numbers lead to unviable zygotes and the baby never develop fully.

Note that during mitosis, sister chromatids are being separated and therefore the number of chromosome copy should not matter much in the general case.

$\endgroup$
1
$\begingroup$

The answer of @Remi.b is true in general case. Still, we can consider at least two mechanisms which will lead to fetus mosaicism.

First one is a mitotic recombination. It is a rare process of recombination in a somatic cell which can result in unequal genotypes in daughter cells. Therefore, if one chromosome of zygote possesses some minute mutation it is possible that after first division only one of daughter cells will have got a mutation. In such case, about half of fetus's cells will be mutation free.

The second possible process is a back mutation. They are such mutations that restore genotype to a state of the wild type. According to this paper, such mutations are not so rare in human cells. As a result, the fetus will consist of both mutated and wild type cells.

It is important to say that such mechanisms are quite rare and will work only for small mutations (i think only for point mutations).

$\endgroup$

Not the answer you're looking for? Browse other questions tagged .