The eldest grandmother, late Miocene †<i>Jenynsia herbsti</i>sp. nov. (Teleostei, Cyprinodontiformes), and the early diversification of the Anablepidae

Phylogenetic comparative studies suggest that the direction of deviation from bilateral symmetry (sidedness) might evolve through genetic assimilation; however, the changes in sidedness inheritance remain largely unknown. We investigated the evolution of genital asymmetry in fish of the family Anablepidae, in which males' intromittent organ (the gonopodium, a modified anal fin) bends asymmetrically to the left or the right. In most species, males show a 1 : 1 ratio of left-to-right-sided gonopodia. However, we found that in three species left-sided males are significantly more abundant than right-sided ones. We mapped sidedness onto a new molecular phylogeny, finding that this left-sided bias likely evolved independently three times. Our breeding experiment in a species with an excess of left-sided males showed that sires produced more left-sided offspring independently of their own sidedness. We propose that sidedness might be inherited as a threshold trait, with different thresholds across species. This resolves the apparent paradox that, while there is evidence for the evolution of sidedness, commonly there is a lack of support for its heritability and no response to artificial selection. Focusing on the heritability of the left : right ratio of offspring, rather than on individual sidedness, is key for understanding how the direction of asymmetry becomes genetically assimilated.

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“…In these datasets, J. obscura often had a large number of autapomorphies (e.g. [47,55]), and its placement was only poorly supported (e.g. [23]).…”

Section: Discussionmentioning

confidence: 99%

Genetic assimilation and the evolution of direction of genital asymmetry in anablepid fishes

et al. 2022

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Two new genera of killifish (Cyprinodontiformes) from the Middle Miocene of the Bugojno Basin, Bosnia and Herzegovina: insights into the lost diversity of Valenciidae

Herbert Mainero,

Vasilyan,

Reichenbacher

2024

Journal of Systematic Palaeontology

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The eldest grandmother, late Miocene †Jenynsia herbstisp. nov. (Teleostei, Cyprinodontiformes), and the early diversification of the Anablepidae

Cited by 2 publications

References 31 publications

Genetic assimilation and the evolution of direction of genital asymmetry in anablepid fishes

Genetic assimilation and the evolution of direction of genital asymmetry in anablepid fishes

Two new genera of killifish (Cyprinodontiformes) from the Middle Miocene of the Bugojno Basin, Bosnia and Herzegovina: insights into the lost diversity of Valenciidae

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