The homologous chromosome pairs in our cells do not carry identical sequences in all loci. This heterozygosity (difference between the two copies) can be altered in cancer: in fact, loss of heterozygosity at many loci is observed in cancer cells, through an increase in either homozygosity (two identical copies) or hemizygosity (i.e. loss of one copy). Researchers can take advantage of this loss of heterozygosity in cancer cells to identify genomic loci that contain cancer-critical genes. What type of gene would you expect to find in chromosomal regions with a loss of heterozygosity? Proto-oncogenes (P) or tumor suppressor genes (T)? Write down P or T as your answer.

Question

Quizplus · Accepted Answer

Once the first copy of a tumor suppressor gene is lost or inactivated, the remaining copy is commonly lost by a less specific mechanism, leading to loss of heterozygosity in the gene as well as in its neighboring loci. This represents a way of finding loci that contain tumor suppressor genes.

The Homologous Chromosome Pairs in Our Cells Do Not Carry