Epigenetics refers to a special kind of hereditary mechanism. epigenetic changes do not change the dna nucleotide sequence, yet their effect on gene expression can last for several generations. in one surprising study, it was found that the grandsons of men who suffered a famine were less likely to die of cardiovascular disease. the experience of famine made some cardio-protective change in the sperm of those grandfathers that was passed on. what type of change was likely responsible?

a. histone acetylation or dna methylation
b. phosphatase levels
c. ubiquitin tagging

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

Dna. we have heard that we are a product of our dna. but where is it? how do we "get" our dna? it is passed to us, from our parents, but in what form? several vocabulary words associated with inheritance are used interchangeably and sometimes, incorrectly. let's see if you can clear this up for someone just learning about inheritance and cell structure.

During the process of two rails or sides break apart and attract new nucleotide bases to form a new and complete strand.