Rarely used stuff isn’t junk DNA. It is still part of the genome, just expressed only under certain conditions (like stress).
Viral sequences do get embedded in host DNA. Some stay mostly inactive, others keep jumping around (and shuffling our genes in usually harmful but occassionally useful combinations) and yet others actually become useful to the host.
Rarely used stuff isn’t junk DNA. It is still part of the genome, just expressed only under certain conditions (like stress).
Viral sequences do get embedded in host DNA. Some stay mostly inactive, others keep jumping around (and shuffling our genes in usually harmful but occassionally useful combinations) and yet others actually become useful to the host.