AP BIOLOGY

Detailed explanation-1: -One of the main differences between retroviruses and LTR retrotransposons is whether they are infectious. Retroviruses are capable of moving between cells, whereas LTR retrotransposons can only insert new copies into the genome present within the same cell, and rely mostly on vertical transmission through generations.

Detailed explanation-2: -Abstract. Human endogenous retroviruses (HERVs) are a family of viruses within our genome with similarities to present day exogenous retroviruses. HERVs have been inherited by successive generations and it is possible that some have conferred biological benefits.

Detailed explanation-3: -Endogenous retroelements are mobile genetic elements that constitute nearly 50% of the human genome. These elements are present in almost all organisms, and it is thought to have arisen from integration of retroviruses into the host genome.

Detailed explanation-4: -Retroviruses and long terminal repeat (LTR) retrotransposons share a common structural organization. The main difference between these retroelements is the presence of a functional envelope (env) gene in retroviruses, which is absent or nonfunctional in LTR retrotransposons.