Butterflies and moths share ancient DNA Blocks

New research conducted by scientists from the Universities of Exeter, Lübeck, and Iwate has revealed fascinating insights into the genetic similarities between butterflies, moths, and Trichoptera, commonly known as aquatic caddisflies. By comparing the chromosomes of various butterfly and moth species, the researchers discovered blocks of chromosomes that are present across all moth and butterfly species, as well as in Trichoptera. These shared blocks of homology indicate a common ancestry dating back over 200 million years.

While butterflies and moths exhibit a wide range of chromosome numbers, ranging from 30 to 300, the study’s findings demonstrate remarkable evidence of shared chromosomal structure throughout evolutionary history. Professor Richard ffrench-Constant from the Centre for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall explained that DNA is organized into individual particles or chromosomes, which serve as the fundamental units of inheritance. Genes located on the same chromosome are typically inherited together and are considered “linked.” However, determining the relationship between chromosomes becomes challenging when the number of chromosomes varies significantly, as is the case with Lepidoptera (butterflies and moths).

To overcome this challenge, the researchers developed a simple technique that examines the similarity of gene blocks on each chromosome. This approach provides a more accurate understanding of how these blocks evolve across different species. The study identified 30 fundamental units of “synteny” (meaning “on the same string” in reference to DNA) that are present in all butterflies and moths and trace back to their sister group, the caddisflies or Trichoptera. These findings shed light on the shared genetic heritage of these insect groups and provide valuable insights into their evolutionary history.

The chromosomes of the African Monarch butterfly. The red dots highlight the ends of each chromosome using a DNA probe linked to a fluorescent reporter. Credit: University of Exeter

Butterflies, widely recognized as important indicators of conservation, are facing declining populations globally due to human activities. Nevertheless, this recent research highlights an additional value they hold as models for studying the evolution of chromosomes.

By investigating the genetic makeup of moths, butterflies, and Trichoptera, scientists have enhanced our scientific comprehension of the evolutionary processes shaping their genes. Moreover, the techniques employed in this study may yield valuable insights into chromosome evolution within other animal or plant groups.

Published in the esteemed journal G3: Genes, Genomes, Genetics, this study contributes to our understanding of butterflies while also emphasizing their significance as a research tool for broader evolutionary studies.

Source: University of Exeter

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