The adverse health effects of smoking can be passed down through multiple generations, according to new experiments conducted at the Los Angeles Biomedical Research Institute. In one experiment, pregnant rats were given nicotine injections that produced asthma in their offspring. What surprised researchers is that third-generation rats (the grandchildren of the smoker rats) also developed asthma. "Nicotine is not only affecting lung cells, [say researchers], but also affecting sex cells in ways that cause the lungs which ultimately develop from those cells to express their genes in the same abnormal ways."
Some biologists are highly skeptical of the recent findings because they appear to run contrary to Darwin's theory of evolution. The suggestion that learned traits, such as a smoking addiction, can be passed down genetically to future generations was initially a theory put forth by the French naturalist Jean-Baptiste Lamarck that rivaled Darwin's evolution. Today, genetic inheritances of learned traits are known as epigenetic changes, a term that refers to the regulation of gene expression by the chemical modification of DNA, or of the histone proteins in which DNA is usually wrapped.
Via Dr. Stefan Gruenwald