Understanding the material base of adaptive evolution has been a central goal in biology dating from at least the Darwin era. A focus on current discussions is whether adaptive evolution is based on many mutations with small and almost equal effects or is driven by one or some mutations that cause significant changes to the characteristics.
Chromosomal rearrangements where large pieces of chromosomes are inverted, moved, deleted or copies, provide a possible source for such long -term “long -term”. However, the characterization of chromosomal rearrangements with usually tested DNA sequence methods was difficult.
Many organisms, including humans, are duplicate, which means they have two sets of chromosomes – one of each parent. The same is true for stick insects. This makes the recognition of chromosomal rearrangements with provocative species when assembling genomes.
In the past, we have averaged data from each set of chromosomes, but the limited accuracy of this method does not tell the whole story. Using newer, molecular and computational approaches that create gradually genome complexes, where the two copies of each chromosome are assembled separately, allowed us to immediately show how complex chromosomal rearrangements allowed insects to adapt to the encryption.
Zachariah Gompert, Evolutionary Biologist, Utah State University
In the US Union’s US Union issue of the American Union of American Union ScienceGompert and his colleagues report adaptive divergence in a cryptic color pattern is degraded with two separate, complex chromosomal rearrangements, where millions of DNA bases are reversed backwards and moved by one part of one chromosome to another, independently in different rods. Contributing writers in the document include Gompert Patrik Nosil’s long -term collaborator and other researchers at the French National Center for Scientific Research (CNRS), along with scientists at the University of Notre Dame, University of Nevada, Reno and Reno. The research is supported by the National Science Foundation and the European Research Council.
Scientists were studied Timema Cristinae Insects with a variety of color designs, collected from two mountains near Santa Barbara, California. Insects that feed with wings are adapted by the two different species of plants to the coastal chaparral habitats. An insect pattern with a stick is green, allowing it to be combined with the lilac of California, while the other athletes are a thin, white stripe on its back, making it almost undetectable among the chamise -like needles.
Gompert and his colleagues have shown that this adaptive difference in color pattern is almost completely explained by the presence of these individual complex, chromosomal rearrangements.
“The new gradual genomic assembly technology used in this study was a crucial part that helped us consider how the color model developed in these insects,” says Gompert, a professor at the USU Biology Department and the USU Ecology Center. “Our findings suggest that chromosomal rearrangements can be more widespread and more complicated than we have previously thought.”
It says that these mutations, despite being large, are easy to lose using traditional DNA sequence approaches.
“Chromosomal rearrangements can be difficult to detect and characterize using typical approaches,” says Gompert. “We are essentially examining the” dark matter “of the genome.”
The structural variant, he says, instead of being rarely, may be regularly available to cause evolution.
“We’re just scratching the surface,” says Gompert. “We have little tools for detecting structural fluctuations, but with improved technology we assume that it plays a more important role in evolution than previously recognized.”
Source:
Magazine report:
Gompert, Z., et al. (2025). The adaptation uses repeatedly complex structural genomic variant. Science. doi.org/10.1126/science.adp3745.
