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6 Cards in this Set
- Front
- Back
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Effects of changes to the structure ot number of chromosomes |
Changes in structure occur in translocation Usually leads to non viable gamates Extra of missing DNA |
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Effects of extra chromosomes |
Downs syndrome -missing chromosome - trisomy 21 |
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Downs syndrom fertilisation |
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Downs x normal fetilisation |
Trisomy 22 and 21 can be tolerated due to the smaller numbers of genes they carry, however other genes such as 1 and 2 are longer, containing morr genes so cannot be tolerated |
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Trisomy |
Happens in oogenesis instead of spermatogenesis Caused by stop start process( older=more stop starting) More likelihood of disjunction is to occur 1 in 700 pregnancies 1 in 100 in women over 40 |
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Phenotypes of downs |
Open flat faces Happy Friendly personality Impact of mental ability Known as mentally retarded |
