Transfer, integration and expression of functional nuclear genes between multicellular species

The sea slug, Elysia chlorotica, is a deep green color due to the presence of intracellular, symbiotic chloroplasts captured from algae during feeding. Several chloroplast proteins, including some that are nuclear-encoded such as FCP, LHC I and LHC 2, are synthesized while the plastids reside in the host cytoplasm, for as long as 9 months. Using PCR, we have identified the sequences for fcp, Lhcv 1 and Lhvc 2 in genomic DNA and mRNA from adult slugs, and from pre-hatched veliger larvae. These results show that the algal nuclear genes are present in the animal cell, are transcribed and are transmitted to the offspring. This is the first demonstration of transfer of functional, inheritable genes between multicellular organisms.