Question

what is a gene chip? ehat are ethical considerations of having our genetic information "out there" in the world ?

Answer 1

A gene chip is usually called a DNA chip or a microarray. It is a small chip in the size of 5x5 inches. It is made of either glass, plastic or silicon. It contains thousands of spots arranged in a square that have small DNA sequences (probes) attached to them and are immobilized. Each spot is about 200 microns in size and accomodates probes of length 15-20 bp. These arrays are added with probes with the help of a mask that has gaps in certain places where the desired nucleotide is added. By adding nucleotides one by one the probes are fixed onto the spots by addition of blocking agents which do not allow any further binding of nucleotides. Now these microarrays have a vast range of applications in checking the mRNA expression of different genes at a time, testing a large sample of gene of any individual, drug therapies which are designed based on an individual's genetic makeup in certain types of cancers and also used in hybridisation experiments. In cancers, the gene expression is measured by designing cDNA to the known mRNA sequence of that gene from a normal cell and probing it onto the microarray which is hybridised with the complementary sequence from the gene of the cancer cell which is labelled with fluorescence. Thus if the gene is upregulated fluorescence is observed when the sequence hybridises with the probe and vice versa.

When you sequence the genome of any individual and store the information in a database, the complete genetic makeup including the mutations and polymorphisms are available. This raises concerns of breach of individual's privacy and also publishing of such information for the purpose of research without the consent of the individual. During population screening the genome of a population is analysed and conclusions are drawn based on the sequences of individuals present in the population and the data is published which may be misguiding and not relevant in few cases. Any individual's genetic information can be easily misused in this era of genomics where there is constant need to manipulate, modify or edit genomic sequences for advancing research in this field. Therefore, strict enforcement of laws is essential to prevent such activities and guarantee full privacy of one's own genetic information.