Non- Disjunction :
Non- Disjunction A mutation is a change in the structure or amount of an organisms genetic material. A mutant is when the change in the genotype effects the phenotype. Non- disjunction
This is when extra chromosomes arise in gametes because the spindle fibres break and can’t pull one or more of the chromosomes apart during meiosis. e.g. Down’s syndrome, an extra chromosome no. 21
Complete non-disjunction :
Complete non-disjunction Complete non- disjunction
This is when all the chromosomes move in the same direction during meiosis.
This results in some diploid gametes forming.
Polyploidal :
Polyploidal If a diploid gamete fuses with a haploid gamete it results in 3 sets of chromosomes etc. If the zygotes are able to survive it results in the organism having many sets of chromosomes this organism is said to be POLYPLOIDAL. Polyploidal is rare in humans but common in plants Polyploidal Plants:
Grow more vigorously
Produce a higher yield
Grow without seeds Useful in farming
Chromosome Mutation :
Chromosome Mutation Chromosome mutation can result in pieces of chromosomes being:
removed- DELETION
rotated and replaced- INVERSION
moved from one place to the other- TRANSLOCATION
copied twice- DUPLICATION
Gene Mutation :
Gene Mutation The structure of genes can change by:
SUBSTITUTION- point change
DELETION- frame shift change
INSERTION- frame shift change
ROTATION- point change
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