I understand that at the molecular level a CRISPR mediated gene drive works by copying the altered gene (and the drive containing CAS enzyme, and guide RNA) into the other chromosome containing the wild type allele through homology directed repair...Lets consider a suppressive drive that is designed to be lethal when the altered gene is present in Both copies of the chromosome (for example maybe organism is likely to die of a heart attack before reaching reproductive maturity)..... In a lethal suppression drive as described above, Where is this copying and homology directed repair happening. In the somatic cells of one of the “parents”, or the germline cells of the parents during meosis/gametogenesis? What happens when a organism containing wild type allele mates with an organism containing the drive?
If the drive and altered gene is copied in the somatic cells of the organism that was inserted in, then wouldn't the organism perish before, being able to pass on the drive/altered gene (given how our suppression drive is designed being lethal if both copies of gene are present)? Or is this copying happening during when the offspring is a zygote (thus all off offsprings somatic cells), or the germline of the offspring? If the copying is occurring in the Zygote stage, all somatic cells of the offspring will contain two copies of the altered gene and will be Homozygous recessive for the altered deleterious gene. Then how will the offspring be able to mate and SPREAD the drive before perishing (or not being able to reproduce). How is it ensured that drive copying only occurs during gametogenesis and does not alter the somatic cells in either parent or offspring? Because it seems to me for the drive and the altered gene to spread it can only happen during meosis/gametogensis...