Question

What is the correct order of expression of the genes listed below in the determination of segmentation in Drosophila(1) Segment polarity genes(2)Hox genes(3)Gap genes(4)Pair rule genes

Answer 1

The correct order of expression of the genes listed below in the determination of segmentation in Drosophila is "Hox genes > Gap genes > Pair rule genes > Segment polarity genes"

Order: 2 > 3 > 4 > 1

Explanation:

The master regulator genes are that guide the creation of specific body segments or structures known as "Homeotic genes". Since these genes are active in segment patterning, the gap genes, pair-rule genes and segment polarity genes are designated as segmentation genes.

• Many animal homotic genes express transcription factor proteins that include a region called the homeodomain or Hox gene.
• The maternal impact genes express transcription factors which regulate the gap gene expression. The distance genes subdivide the embryo approximately along the anterior / posterior axis.
• The gap genes encode transcription factors which control the pair-rule expression of genes. The pair-regulated genes split the embryo into segment pairs.
• The pair-rule genes encode transcription factors which control the function of the polarity genes in the segment. The polarity genes in the segment determined each segment's anterior or posterior axis.