There is recent study on the extension of CRISPR with a system called gene drive, that uses CRISPR as a stepping stone. CRISPR gene drive is one of the most powerful and alarming new tool in the science world today. Some researchers though of what if CRISPR inserted not only on the new gene but also a machinery that does the cutting and pasting. In other words, CRISPR also copied and pasted itself. The result will be a perpetual motion machine for gene editing. CRISPR gene drive created by a scientist name Esvelt, which guarantees that a trait will get passed on, but if it is used in the germline cells, it will automatically copy and paste the new gene into both chromosomes of every single individual. It is like a global search and replace, or in science terms, it makes a heterozygous trait homozygous instead.
There is a research using the gene drive to create mosquitoes carrying anti-malaria gene. The result given, the Mendelian genetics says when a male and a female mate, their baby inherits half of its DNA from each parent. As a result, if the original mosquito was aa and the new mosquito is aB, where B is the anti-malarial gene, the babies should come out in four permutations: aa, aB, aa, Ba. Instead, with the new gene drive, they all came out aB. Biologically, that should not even be possible. However, CRISPR gene drive make it completely possible for any researchers to achieve this miracle.
Personally, this new tool is pretty alarming. CRISPR is fascinating enough, but with new add-on feature, an entire population's genome can be change very rapidly, especially with a fast reproductive cycle that the mosquitoes have. This can lead to an earlier evolution than just solely depend on mutation slowly introduce to a population or any other effects on the population.