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Updated: Jun 7, 2025
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One-Step Leaping Evolution from an Autosomal Pair to the Heteromorphic Sex Chromosomes
Ikuo Miura1,2, Foyez Shams2, Tariq Ezaz2
1Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Japan.
Summary
We propose a novel pathway for sex chromosome evolution, bypassing gradual inversions. Interspecific hybridization can rapidly create new, heteromorphic sex chromosomes by introducing inverted genetic material, accelerating divergence.
Area of Science:
- Evolutionary genetics
- Comparative genomics
- Reproductive biology
Background:
- Sex chromosomes typically evolve from autosomes through sequential inversions, forming non-recombining strata.
- This process leads to gene divergence and degeneration of the Y or W chromosome.
Purpose of the Study:
- To challenge the conventional theory of sex chromosome evolution.
- To propose a rapid evolutionary pathway for heteromorphic sex chromosomes.
Main Methods:
- Analysis of two frog species exhibiting rapid sex chromosome formation.
- Investigating the role of interspecific hybridization and introgressed inverted chromosomes.
Main Results:
- Demonstrated direct evolution of heteromorphic sex chromosomes from an autosomal pair via introgressed inverted chromosomes.
- Observed the immediate formation of a distinct non-recombining region post-hybridization.
Conclusions:
- Interspecific hybridization offers a shortcut for heteromorphic sex chromosome evolution.
- Introgressed inverted chromosomes may confer adaptive advantages, influencing morphology, behavior, and hybrid fitness.
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