1-yes,Scientists have isolated a gene sequence that appears to determine how fast our bodies age, the first time a link between DNA and human lifespan has been found
The DNA that makes up your genes is entwined in 46 chromosomes, each of which ends with a telomere, a stretch of DNA that protects the chromosome like the plastic tip on a shoelace. Telomeres are quite long at birth and shorten a bit every time a cell divides; ultimately, after scores of divisions, very little telomere remains and the cell becomes inactive or dies. And because elderly people generally have shorter telomeres than younger people, scientists believe that telomere length may be a marker for longevity as well as cellular health
2-yes...explanation is given in 1st