Answer/Explanation:
(1) a mutation in the coding region, resulting in an inactive protein
To check to see if there is a mutation, you could extract the DNA from the cancer cells and then perform PCR to amplify the gene of interest. You could then perform sanger sequencing and compare the sequence to the normal gene to see if a mutation is present. To test the effect of the mutation, you would want to see if an active protein has been formed.
To see if a normal sized protein has been formed, you could perform a western blot, comparing the protein band to the WT protein band. If the protein is absent or much smaller, it is likely not a functional protein.
(2) epigenetic silencing at the promoter of the gene, resulting in reduced transcription.
To check for changes in the epigenetic landscape of the promoter, you could perform chromatin immunoprecipitation by extracting the chromatin from the tumour cells and using antibodies for different chromatin marks to see what has changed between the normal cells and the tumor cells. E.g. H3K9me3, H3K27me3. You would perform a pull down with the antibody of interest and then PCR for your promoter to specifically look at changes at that gene compared to normal cells. To test DNA methylation, you could perform bisulfite sequencing.
To see how transcription is affected, you could extract RNA from the tumor and normal cells, and compare the levels of RNA between the two samples by qRT-PCR
Mosses,ferns and thallophytes
The KT boundary marks a mass extinction event. the KT boundary is the time between the Cretaceous and Tertiary periods. An asteroid hit the earth at the end of the Cretaceous and that caused the end of the Cretaceous period. Before the KT boundary, pollen from angiosperms and gymnosperms is high. After the meteor hits the earth, a mass extinction occurs and the amount of pollen from gymnosperms and angiosperms decreases dramatically, while the amount of spores from ferns increases. During the Cretaceous period there were many species of gymnosperms and angiosperms but they disappeared at the KT boundary, when the asteroid hit the earth.
Answer:
Most damage to DNA is repaired by removal of the damaged bases followed by resynthesis of the excised region. Some lesions in DNA, however, can be repaired by direct reversal of the damage, which may be a more efficient way of dealing with specific types of DNA damage that occur frequently.
