Jerome Jullien from the Welcome Trust CRUK Gurdon Institute in Cambridge experimented with frogs to see if more than just DNA is passed on to the second generation offspring. Sperm contain something called epigenetic tags which are “chemical switches attached to the genomes of sperm.” (It is important to understand that epigenetics does not alter an organism’s DNA.) In order to test if these sperm epigenetics influence offspring Jullien used two types of sperm; regular frog sperm and spermatids which had different epigenetic tags. They then injected the sperm and spermatid into genetically engineered eggs which took away some of the epigenetic tags (with specific enzymes) on the sperm. This lead to abnormal gene expression causing problems for the offspring.
This basically shows that a male does not simply pass down his DNA to his offspring but other factors like epigenetic tags can also effect the life of their kids. As Jullien says, “The obvious implication is that whatever experiences the father has in life that end up epigentically modifying sperm cells might also be transmitted to the offspring and affect their genetic development and characteristics.” There is still disagreement over whether epigenetic tags on sperm influence offspring. For example some feel the experiment tested was not realistic because the frogs were not exposed to different environments as a human would be in his lifetime. What do you think; would epigenetic tags on male sperm have an effect on a mans offspring?