Mapping the Fruit Fly’s Brain: A Milestone in Neuroscience

Why in the news?

Scientists have successfully mapped the entire brain of an adult fruit fly, a milestone that could advance understanding of brain function and mental health treatments in humans and other animals.

Mapping the Fruit Fly's Brain: A Milestone in Neuroscience

Research Achievement:

  • Scientists have successfully mapped the entire brain of an adult fruit fly, marking the first detailed survey of an adult animal’s brain.
  • The findings, published in Nature, are a significant step toward understanding the human brain, potentially aiding in the treatment of mental health conditions like Parkinson’s and depression.
  • The project involved contributions from hundreds of scientists and citizen scientists worldwide. 

Methodology:

  • Mapping began in 2013, with the fruit fly’s brain submerged in a chemical bath, solidifying it into a block.
  • Researchers meticulously shaved off ultra-thin layers of the block and used microscopes to capture images.
  • In total, they took 21 million photos across 7,050 sections to create a comprehensive brain map.

Significance of the Findings:

  • Detailed more than 50 million connections among over 139,000 neurons, categorising them into 8,453 distinct types—this constitutes the largest catalogue of cell types in any brain.
  • Insights gained include understanding how different cell types function, how the fly’s eyes process motion and colour, and the discovery of “hub neurons” that may enhance information flow.
  • Although the human brain is more complex, fundamental communication principles among neurons remain similar, offering potential insights into human brain function.

About Drosophila melanogaster:

  • Commonly known as the fruit fly; widely used in genetic, physiological, and evolutionary studies.
  • Greek origin: Drosophila means “dew lover”; melanogaster means “dark gut”.
  • Wild-type flies have brick red eyes and yellowish-brown bodies with black rings.
  • Females are approximately 5 mm long; males are smaller and darker with distinctive sex combs.

Biology and Development:

  • Development period: 7 days at 28 °C; 11 days at higher temperatures.
  • Females lay around 400 eggs in decaying fruit; hatching occurs after 12-15 hours.
  • Larvae complete development in 4 days, feeding on microorganisms and fruit.
  • Lifespan: approximately 30 days at 29 °C.

Research Significance and Contributions:

  • Ideal for genetic studies due to small size, easy culture, and short generation time (2 weeks).
  • Complete genome sequenced; contains about 165 million bases and 14,000 genes.
  • Thomas Hunt Morgan’s work in the early 1900s established Drosophila as a model for heredity and earned him a Nobel Prize.
  • 75% of human disease genes have identifiable matches in fruit flies; used to study various diseases and biological processes, including neurodegenerative disorders and cancer.

Sources Referred:

PIB, The Hindu, Indian Express, Hindustan Times