I Got It From My Mama - or Maybe a Protist?

In a new study from the University of Cambridge , researchers are finding that not all human genes are ancestrally inherited. While there is no doubt that bacteria partake in horizontal gene transfer, it's been thought that complex animals only receive their genes from their parents. This new study, however, challenges the established idea that there is no horizontal gene transfer in more highly developed animals. In the study, the genomes of four nematode species, twelve fruit fly species, and ten primate species (including humans) were examined and then compared with that of the other species. The researchers then estimated how long ago the similar genes were acquired, and how likely it was that these genes were foreign in origin. Almost 150 human genes were identified as foreign, and thus acquired through horizontal gene transfer, and nearly all of them related to enzymes involved in metabolism. Along with identification, the researches were also able to determine where the genes most likely came from, finding that most of the genes were transferred from bacteria and protists, while some were from viruses and fungi. While some of the other species involved in this study continue to receive genes from outside sources, it's likely that humans and other primates haven't procured genes through horizontal transfer since the common ancestor species  - probably around 5-8 million years ago. The researchers of this study hope that their findings lead to a better understanding of the genomes of complex animals, and hope that bacterial sequences in DNA shouldn't always be written off as bacterial contamination in genomic studies.