Behavioural individuality in clonal fish arises despite near-identical rearing conditions.
Level 5 - mechanism / opinion, no new human data
Animal experimental study
PubMed 28513582 · doi:10.1038/ncomms15361
What was done
Researchers conducted ontogenetic experiments using the clonal Amazon molly (*Poecilia formosa*) to evaluate whether eliminating genetic variation, standardizing rearing conditions, and restricting social contact prevents the emergence of individual behavioral variation. Genetically identical fish were isolated immediately after birth in highly standardized environments, and the effect of varying levels of social experience during ontogeny on behavioral individuality was tested.
What was found
The abstract reports no numerical values. It reports two qualitative outcomes: substantial individual variation in behavior emerged among genetically identical fish reared in isolation in standardized environments, and increasing levels of social experience during ontogeny did not affect the degree of individual behavioral variation.
Why it matters
These findings challenge the assumption that behavioral individuality requires genetic diversity or distinct environmental and social experiences, pointing instead toward developmental stochasticity as an intrinsic source of individuality.
Limits
The abstract provides no sample sizes, specific behavioral metrics, effect sizes, or statistical certainty measures. The study was conducted entirely in a single clonal fish species (*Poecilia formosa*), limiting direct generalizability to other taxa or sexually reproducing vertebrates.
Cited by
- supports Genetically identical animals—such as inbred mice, nine-banded armadillo quadruplets, and clonal fish—exhibit emergence of individual behavioral variability even when reared in identical environments, a phenomenon scientists term developmental noise.