Summary
Gap, pair-rule and segment polarity genes progressively divide the fly embryo into segments.
In depth
Hierarchy: maternal genes, gap genes (Krüppel), pair-rule genes (even-skipped) making seven stripes, then segment polarity genes (engrailed, wingless) setting pattern in each of 14 parasegments. Nüsslein-Volhard and Wieschaus won the 1995 Nobel Prize.
Pair-rule genes form stripes in alternate segments; segment polarity genes set the front and back of each segment. Hox genes then give segments identity.
Remember: segmentation genes act in a cascade, each level refining the next.
Frequently asked questions
What is Segmentation Genes?
Gap, pair-rule and segment polarity genes progressively divide the fly embryo into segments.
Which area of biology covers Segmentation Genes, and how advanced is it?
Segmentation Genes is one of the 54 topics in Developmental Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Maternal Effect Genes, Hox Genes, Limb Development.
Can you give an example of Segmentation Genes?
Gap mutants miss several adjacent segments.
What should I learn before Segmentation Genes?
Work through the Beginner topics in Developmental Biology first, such as Fertilisation, Zygote, Embryo, then return to Segmentation Genes. Intermediate topics assume the Beginner vocabulary.
What topics are related to Segmentation Genes?
The closest topics to Segmentation Genes are Maternal Effect Genes, Hox Genes, Limb Development, Induction. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Segmentation Genes?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Segmentation Genes. To practise the whole of Developmental Biology, use the Developmental Biology quiz.
How is Segmentation Genes different from Maternal Effect Genes?
Segmentation Genes: Gap, pair-rule and segment polarity genes progressively divide the fly embryo into segments. Maternal Effect Genes: Mother's mRNAs deposited in the egg, such as bicoid in Drosophila, set up the embryo's polarity. Read both side by side and note what each one explains.
How should I study Segmentation Genes step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Maternal Effect Genes and explain the difference aloud. Finally, take the Developmental Biology quiz and come back to this page for any question you miss.