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mutation (1 Viewer)
- Thread starter bobbie212
- Start date
lukebennett
Happy Member
i dont think it needs to be in gametes. an allele can be expressed in just one cell-the cell whose DNA has been mutated for one reason or another as this triggers the production of a different polypeptide/protein/enzyme thus a different trait of characteristic.
pink_and_blue
New Member
Mutations
A mutation is a change in a gene. It involves some change in the base sequence of the DNA composing the gene. It can be a substitution of one or more bases for others, deletion (omission) of bases or insertion (addition) of bases. If the mutation takes place in an essential part of the gene, the protein that is specified by the gene will be changed also. The disease sickle cell anaemia is cuased by the subsitiution of only one base in the DNA.
Many proteins are enzymeas that catalyse living chemical reactions. The result of a mutation can be abnormal effect due to an altered chemical reaction. An example of this is albinism, in which a mitation (altered gene) cuases the production of an altered enzyme for sythesising the skin pigment melanin. Albinos are characterised by pale skin and pink eyes. This results in dangerous side-effects such as increased susceptibility to skin cancer.
Mutations may be an advantage ) favourable) or a disadvantage (unfavourable) to an organism. More commonly they are unfavourable. They occur naturally due to the possibility of error when genes are copied, so there is a small percentage of natural mutations in a population for every gene. It is believed that mutations play a significant role in evolution. Favourable mutations produce variations that may be naturally selected, resulting in evolution. Note, hoever, that some mutations may be neutral, that they are neither an advantage nor a disadvantage except when a significant chnage occurs in the environment. For example, a population of bacteria may conatin a few mutants (mutants are organisms conatining a mutation) that have a gene resistant to a particular antibiotic. The general population and the mutants will remain unchanged until the antibiotic is introduced. There will be an increase in the numbers of mutants and a decrease in the numbers of regular population.
The natural rate of mutation can be increased significantly by certain environmental factors called mutagens. They include certain chemicals, X-rays and UV light. Some mutations are believed to be changes in the genes that control cell division and this can reult in cancer.
Mutations are a result of genetic diversity (variation) in both sexual and asexual organisms. They are the cause of genetic variation in asexual organisms.
A mutation is a change in a gene. It involves some change in the base sequence of the DNA composing the gene. It can be a substitution of one or more bases for others, deletion (omission) of bases or insertion (addition) of bases. If the mutation takes place in an essential part of the gene, the protein that is specified by the gene will be changed also. The disease sickle cell anaemia is cuased by the subsitiution of only one base in the DNA.
Many proteins are enzymeas that catalyse living chemical reactions. The result of a mutation can be abnormal effect due to an altered chemical reaction. An example of this is albinism, in which a mitation (altered gene) cuases the production of an altered enzyme for sythesising the skin pigment melanin. Albinos are characterised by pale skin and pink eyes. This results in dangerous side-effects such as increased susceptibility to skin cancer.
Mutations may be an advantage ) favourable) or a disadvantage (unfavourable) to an organism. More commonly they are unfavourable. They occur naturally due to the possibility of error when genes are copied, so there is a small percentage of natural mutations in a population for every gene. It is believed that mutations play a significant role in evolution. Favourable mutations produce variations that may be naturally selected, resulting in evolution. Note, hoever, that some mutations may be neutral, that they are neither an advantage nor a disadvantage except when a significant chnage occurs in the environment. For example, a population of bacteria may conatin a few mutants (mutants are organisms conatining a mutation) that have a gene resistant to a particular antibiotic. The general population and the mutants will remain unchanged until the antibiotic is introduced. There will be an increase in the numbers of mutants and a decrease in the numbers of regular population.
The natural rate of mutation can be increased significantly by certain environmental factors called mutagens. They include certain chemicals, X-rays and UV light. Some mutations are believed to be changes in the genes that control cell division and this can reult in cancer.
Mutations are a result of genetic diversity (variation) in both sexual and asexual organisms. They are the cause of genetic variation in asexual organisms.
lukebennett
Happy Member
your post is very detailed and informative but it doesnt really answer the question bobbie212 asked: does mutation lead to generation of new alleles only when it occurs in the gametes?
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As far as the course outcomes require, we only need to know that a mutation on a somatic cell will not be passed down onto the next generation, whilst a mutation in the gametes will be.
I assume like Luke that it can lead to new alleles, unless the trait for uncontrollable mitosis (see cancer) is present in all cells with or without a mutation?
I assume like Luke that it can lead to new alleles, unless the trait for uncontrollable mitosis (see cancer) is present in all cells with or without a mutation?
lukebennett
Happy Member
i dont know if we do need to know much more than how it is passed on. if a mutation in a gene occurs when gametes are it will be passed on when it is replicated etc. the allele can be seen in just one cell at times perhaps like a skin pigmentation or freckle. freckles and pigments however are not passed.
= Jennifer =
Active Member
isn't this dot point the one where you talk about deletions, insertions, substitutions of bases??
thejosiekiller
every me
does mutation lead to generation of new alleles only when it occurs in the gametes?
this would only be so if these new alleles were to be passed on through inheritance to the next generations, but the question asks for a new generation in alleles (ie base sequences in the dna)- its really a tricky question, but i would say yes explaining how mutations are carried on through inheritance to the next generation where these mutattion favourable or not become part of a population.
the example for sickle cell anaemia is a good example for mutations that occur and are passed on to the next generation when it becomes embedded in the gamete.
this would only be so if these new alleles were to be passed on through inheritance to the next generations, but the question asks for a new generation in alleles (ie base sequences in the dna)- its really a tricky question, but i would say yes explaining how mutations are carried on through inheritance to the next generation where these mutattion favourable or not become part of a population.
the example for sickle cell anaemia is a good example for mutations that occur and are passed on to the next generation when it becomes embedded in the gamete.