Scientific advances have unlocked some of the ‘source code’ of living organisms, where by splicing genes from, say, arctic salmon into strawberries, or mice into chickens, we can produce strains of plants and animals which grow better, are more resilient, and are more beneficial economically or otherwise.

While discussion abounds regarding the long-term health effects of these developments, what is the Torah’s view on such manipulation? Do the ethos of kilayim preclude meddling in G-d’s domain? Or does the command to “fill the earth and subdue it” (Bereshis 1:28) provide the ethical mandate to do just that?

What are the Halachic ramifications? Is the act of implanting the gene –in flora or fauna- a violation of kilayim? What is the kosher status of the resulting hybrids? Does the status of the donor carryover to the recipient? What if the transferred genes affect the presence of the traditional kosher signs? (a tuna with no scales, a shark with scales)? Is an Esrog which has been thus modified considered a Murkav, disqualifying it from use for the Mitzvah?

Is there a spiritual effect? Do the characteristics of those animals which the Torah deems negative carry over into the new creature? Would consuming this (otherwise Kosher) creature bring spiritual coarseness (timtum halev)?

A collection of Tshuvos and articles in Hebrew and English.