gene mutation

• why is it difficult to identify how most inherited characteristics are controlled?


  This type ofinterplay between alleles, especially when traits are influenced by multiple genes, makes predicting inheritance difficult, if not impossible. A small number of traits are influenced primarily by a single gene.
• what is a mutation?

  Mutation creates slightly different versions of the same genes, called alleles.
• how can mutation cause variation?


  causes a change in an allele
• which kind of cell division could produce a mutation in: a gamete, a body cell?


  meiosis, mitosis
• explain why the risk of develouping skin cancer can increase with the amount of sunlight your skin recieves?


  sunlight contains ultraviolet radition that can cause mutations in skin cells, which can result in skin cancer
• explain why a mutation does not always produce a change in characteristic?


  mutations can occur in different parts of a gene ans so may only have a small effect on the protein that is produced. many other mutations will not change the protein at all and so have no effect on the phenotype.
• give two ways in which information about a persons genome could be useful in medicine: genetic testing for inherited disorders, tailoring medicine to an individual
• explain how mutation can lead to variation in the phenotype of an organism? mutation can lead to a change in the DNA sequence of an organism
• different people have different eye colours. explain why there is variation in human eye colour?


  ,
• gene for eye colour?

  oca2
• what is melanin?

  a pigment that gives color to skin and hair and protects against UV light
• a blue iris contains little melanin while a brown iris contains a lot of melanin
• what does the oca2 gene do?

  controls the amount of melanin produced
• melanin is a protein
• a change in a gene that creates a new allele is called a mutation, mutations occur during cell division
• sometimes a mutation produces an allele that causes a big change in the protein that is produced. this will effect how the body works. however, mutations can occur in different parts of a gene ans so may only have a small effect on the protein that is produced. many other mutations will not change the protein at all and so have no effect on the phenotype.
• the alleles we have can effect how medicines work in the body.