Scientists discover a new member of an endangered pupfish species native to south-central New Mexico. Previously considered as one species of conservation concern, genetic evidence suggests the existence of two species. Published findings in the Proceedings of the National Academy of Sciences by researchers from Purdue, Ohio State, Auburn, and Texas A&M universities.
Unusual Evolutionary Process
- Genetic drift, rather than natural selection, drove the evolution of two species.
- Rapid divergence occurred, about 400 times faster than typical mammalian speciation.
- Cyprinodon tularosa, an endangered species, native to the Tularosa Basin.
Genetic Study
- Whole-genome sequencing revealed significant differences between populations.
- The role of selection as the driving force was considered due to varying environments.
Drift Speciation
- High levels of genetic drift over the last 5,000 years led to divergence.
- Factors favoring genetic drift over natural selection: small populations, geographic isolation, and harsh desert ecosystem.
Geological Influence
- The Carrizozo lava flow likely acted as a barrier contributing to speciation.
- Genomic and geological data support the divergence around 5,000 years ago.
Population Dynamics
- Ancestral populations experienced stability followed by bottlenecks around 2,500 years ago.
- Bottlenecks caused severe reductions in population size, affecting genetic drift.
Conservation Implications
- Previous conservation measures focused on two populations.
- Recommendations for species-level classification revision and naming the new species “the enchanted pupfish.”
Multiple Choice Questions (MCQs):
- What is the driving force behind the evolution of two pupfish species?
- A) Natural selection
- B) Genetic drift
- C) Environmental adaptation
- D) Hybridization
- Answer: B) Genetic drift
- How much faster did the White Sands pupfish species diverge compared to average mammalian speciation?
- A) 100 times faster
- B) 200 times faster
- C) 300 times faster
- D) 400 times faster
- Answer: D) 400 times faster
- What geological event likely contributed to the speciation of the new pupfish species?
- A) Earthquake
- B) Volcanic eruption
- C) Glacial movement
- D) Tornado
- Answer: B) Volcanic eruption
- What is the term used to describe the sharp reductions in population size experienced by ancestral pupfish populations?
- A) Population explosion
- B) Genetic bottleneck
- C) Population migration
- D) Speciation event
- Answer: B) Genetic bottleneck
- What recommendation do the researchers make regarding the classification of the new pupfish species?
- A) Maintain the current classification
- B) Merge with other pupfish species
- C) Revise to species level
- D) Classify as a subspecies
- Answer: C) Revise to species level