senorfletch

I would like to understand more about endogenous retroviruses and how they are classified. Are there any markers or characteristics that distinguish them from other transposons or other DNA sequences? I am interested because I engaged with a creationist that is saying in response my assertion that ERVs are evidence of evolution, his words : "EVRs were supposed to be *recent* evolutionary addenda not absolutely essential to the earliest stages of embryogenesis. They different from mammal to mammal. They have been consistently shown in the scientific literature to NOT be vestiges of, for ex, a shared, discarded piece of DNA, but rather the scaffolding and the switch stations to current morphological development. That scuttles the nature of EVRs as being an argument for common ancestry, shared and useless old genetic material.” He is using this as an argument that these ERVs cannot be ERVs because they must necessarily be present for embryo development. I’m not exactly sure how to respond to this. Any sources or info would be appreciated. My background is in a bachelors degree in chemistry so I'm not the greatest at genetics.