Question

1) If you were looking for a gene that codes for a very small protein in the contents of a PCR reaction run out on an electrophoresis gel, where would you look for this small protein gene and why?

2) Cystic fibrosis is a genetic condition caused by a recessive gene.   If two parents who are both heterozygous for the gene that causes cystic fibrosis have children, what are the chances of those children having cystic fibrosis and why?

3) What is more likely to cause a harmful side-effect for an organism a mutation in the coding or the non-coding region of that organism’s DNA? Why?

4) Why do you have non-coding areas of DNA?

Answer 1

1. Gel electrophoresis is a technique used to seperate DNA fragments according to their size.Small fragments move faster in the gel compared to large fragments.Else we can compare the size of the fragments with the reference ladder .
2. Heterozygous means out of the two genes one is dominent and other is recessive.or the traits or alleles inherited from parents are different.Cystic fibrosis is caused by the mutations in the CFTR protein and If two carriers have child there is 1 in 4 chance or 25% chance the child gets the disease.
3. Coding regions codew for proteins and non coding regions do not code for proteins.If mutations occur in the coding regions will effect the organism because the mutions in the regions may alter the splicing of mRNA and inturn significantly alter the gene product.
4. Non coding DNA sequences are used to produce functional non coding RNA molecules like transfer RNA,Ribosomal RNA and regulatoy RNA.