Biology subjects

Borbora, A. S.

Publications and source records attributed to Borbora, A. S..

3 recordsLinked to original sources

bioRxiv2026

Temporal niche partitioning through olfactory cell type evolution

Temporal niche partitioning enables species to use the same resource at different times, but the underlying mechanisms are unknown. We show that Drosophila sechellia, a specialist on Morinda citrifolia noni, exhibits narrow temporal preference for the most toxic, ripe fruit, reducing exposure to competition, parasitization and microbial infection that can occur on other stages. Chemical analysis highlighted ketones as signature odors of ripe noni. Comparative single-cell transcriptomic atlases revealed that D. sechellia has co-opted expression of a larval ketone receptor, Or45a, in an adult olfactory neuron population. The novel expression of Or45a can be ascribed solely to cis-regulatory changes and is sufficient to confer physiological sensitivity to ripe noni. Importantly, Or45a is required for D. sechellia's ripe noni preference, acting redundantly with a second ketone receptor, Or85c/b, whose neuron population has expanded in D. sechellia. Our results provide an unprecedented link between cell type evolution and ecologically-advantageous, temporal niche partitioning.

neuroscience↗

bioRxiv2026

Laboratory and wild Drosophila sechellia have conserved niche specialization phenotypes

A major challenge to investigating the proximate causes of ecological adaptation is the difficulty of studying the phenotypes of organisms in their natural environments. By necessity, many studies seeking to determine the genetic and cellular basis of adaptation therefore investigate potentially adaptive phenotypes under laboratory conditions where organisms are more easily experimentally manipulated. For laboratory models, it remains unclear if organisms maintained long term under laboratory conditions are representative of relatives in their natural environment. In recent years, Drosophila sechellia, a specialist species endemic to the Seychelles, has emerged as a (neuro)genetic model for studying the molecular basis of ecological adaptation. A multitude of studies have investigated the genetic and cellular basis of various aspects of this species specialization in a laboratory setting. However, the vast majority of these studies use laboratory strains of D. sechellia that were collected many decades ago, and have been maintained under conditions very different from their natural niche. Thus, it remains unclear if and how these strains resemble their wild counterparts. Here, we compare the phenotypes of these laboratory strains with recently-collected wild D. sechellia to ask if laboratory strains display a loss or degradation of phenotypes potentially involved in their specialization resulting from their long-term laboratory maintenance. Across several behavioral and anatomical phenotypes, we find a high degree of similarity between wild-caught and laboratory-maintained strains. Our results suggest that studies of the molecular mechanisms underlying D. sechellias phenotypes associated with specialization are likely representative of the evolution of these flies in the wild.

evolutionary biology↗

bioRxiv2025

Multilayer regulation underlies the functional precision and evolvability of the olfactory system

Sensory neurons must be reproducibly specified to permit accurate neural representation of external signals but also able to change during evolution. We studied this paradox in the Drosophila olfactory system by establishing a single-cell transcriptomic atlas of all developing antennal sensory lineages, including latent neural populations that normally undergo programmed cell death (PCD). This atlas reveals that transcriptional control is robust, but imperfect, in defining selective sensory receptor expression. A second layer of precision is afforded by the intersection of expression of functionally-interacting receptor subunits. A third layer is defined by stereotyped PCD patterning, which masks promiscuous receptor expression in neurons fated to die and removes "empty" neurons lacking receptors. Like receptor choice, PCD is under lineage-specific transcriptional control; promiscuity in this regulation leads to previously-unappreciated heterogeneity in neuronal numbers. Thus functional precision in the mature olfactory system belies developmental noise that might facilitate the evolution of sensory pathways.

developmental biology↗