Nondisjunction in chromosomes Watch

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guera88
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Report Thread starter 13 years ago
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Can anyone hlep me with this BIO question on genetics?

What would happen if there were nondisjunction in the sex chromosomes?

Describe the event of nondisjunction of homologous chromosomes?

Thanks in advance! I'm having a hard time with this on-line BIO course!
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Golden Maverick
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Report 13 years ago
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(Original post by guera88)
Can anyone hlep me with this BIO question on genetics?

What would happen if there were nondisjunction in the sex chromosomes?

Describe the event of nondisjunction of homologous chromosomes?

Thanks in advance! I'm having a hard time with this on-line BIO course!
Nondisjunction in the sez hormones can cause certain diseases - XXY = Klinefelter Syndrome
- this causes mental retardation and infertility
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Revenged
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(Original post by Golden Maverick)
Nondisjunction in the sez hormones can cause certain diseases - XXY = Klinefelter Syndrome
- this causes mental retardation and infertility
lol, well nasty!

Non disjunction is when the chromosomes fail to separate during meiosis.

For example, for my bio course we show this using Down's Syndrome, which is an example of polysomy, where there is one too many (or too few) chromosomes in an individual.

In a 'normail individual', failure of the chromosome-21 to separate during meiosis causes one gamete to be produced having 2 copies of chromosome-21 and one gamete having no copies of chromosome-21.

After fertilisation occurs, one individual will have three copies of chromosome-21 and so have Down's syndrome. The other individual will have only one copy of chromosome 21 and so will die.

Also, non-disjuntion can happen for all the chromosomes in an organism. This causes the number of chromosomes double, which is called 'polyploidy' and only really happens in plants. For example, a diploid (2n) plant could become tetraploid (4n) due to self polyploidy. It's Crazy!

Polyploidy is where there is three or more sets of chromosomes in a cell.
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guera88
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Report Thread starter 13 years ago
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(Original post by Revenged)
lol, well nasty!

Non disjunction is when the chromosomes fail to separate during meiosis.

For example, for my bio course we show this using Down's Syndrome, which is an example of polysomy, where there is one too many (or too few) chromosomes in an individual.

In a 'normail individual', failure of the chromosome-21 to separate during meiosis causes one gamete to be produced having 2 copies of chromosome-21 and one gamete having no copies of chromosome-21.

After fertilisation occurs, one individual will have three copies of chromosome-21 and so have Down's syndrome. The other individual will have only one copy of chromosome 21 and so will die.

Also, non-disjuntion can happen for all the chromosomes in an organism. This causes the number of chromosomes double, which is called 'polyploidy' and only really happens in plants. For example, a diploid (2n) plant could become tetraploid (4n) due to self polyploidy. It's Crazy!

Polyploidy is where there is three or more sets of chromosomes in a cell.

Thanks a lot! i think I got it now!
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