Conservation demands safe gene drive
Normally, we receive 1 of 2 copies of a given gene from either parent, with a 50:50 chance of each copy being passed on. Gene drive systems distort that rule, promoting the inheritance of a particular copy of a gene from the parent to offspring. (a) CRISPR-based gene drive systems cut the equivalent allele on the wild-type chromosome, causing the cell to copy them via homology-directed repair. (b) Converting heterozygotes to homozygotes in the germline guarantees inheritance, enabling rapid spread through populations. This distortion in and of itself is relatively harmless, but when coupled to a genetic trait that affects an individual’s survival or ability to reproduce, it becomes a powerful tool that can be used for population control or even local elimination. CRISPR, Clustered Regularly Interspaced Short Palindromic Repeats.