Model organisms are really important for understanding how genes work during growth and development.

1. Types of Model Organisms:

   • Drosophila melanogaster (fruit fly): More than 75% of genes that cause diseases in humans can also be found in fruit flies.
   • Mus musculus (mouse): Mice share about 99% of their genes with humans, helping us learn about how mammals grow.
   • Caenorhabditis elegans (nematode): This tiny worm has only 1,000 body cells, which makes it easy to study how its cells develop.

2. Learning About Gene Regulation:

   • Research has shown that when multicellular organisms grow, they use over 250 special proteins called transcription factors.
   • Important pathways that help control development, like the Hedgehog and Notch pathways, are similar in many different species.

3. Genetic Techniques:

   • CRISPR/Cas9 is a tool that allows scientists to change specific genes. It helps researchers study what these genes do with a success rate of over 90% in many different organisms.