Table 1 Lamarckian and quasi-Lamarckian phenomena
Phenomenon | Biological role/function | Phyletic spread | Lamarckian criteria | ||
|---|---|---|---|---|---|
| Â | Â | Â | Genomic changes caused by environmental factor | Changes are specific to relevant genomic loci | Changes provide adaptation to the causative factor |
Bona fide Lamarckian | |||||
CRISPR-Cas | Defense against viruses and other mobile elements | Archaea and bacteria (present in ~1/3 sequenced genomes) | Yes | Yes | Yes |
piRNA | Defense against transposable elements in germline | Animals (apparently, all) | Yes | Yes | Yes |
HGT (specific cases) | Adaptation to new environment, stress response, resistance | Archaea, bacteria, unicellular eukaryotes | Yes | Yes | Yes |
Quasi-Lamarckian | |||||
HGT (general phenomenon) | Diverse innovations | Archaea, bacteria, unicellular eukaryotes | Yes | No | Yes/no |
Stress-induced mutagenesis | Stress response/resistance/ adaptation to new conditions | Ubiquitous | Yes | No or partially | Yes (but general evolvability/ Adaptability enhanced as well) |