Pair-rule genes are a class of segmentation genes first identified in Drosophila melanogaster. In Drosophila, these genes act to translate non-periodic information produced by the overlapping patterns of gap gene expression into patterns of gene expression in every other segment.
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What pairs rule genes?
Pair-rule genes are a class of segmentation genes first identified in Drosophila melanogaster. In Drosophila, these genes act to translate non-periodic information produced by the overlapping patterns of gap gene expression into patterns of gene expression in every other segment.
What is pair-rule gene in biology?
A pair-rule gene is a type of gene involved in the development of the segmented embryos of insects. Pair-rule genes are expressed as a result of differing concentrations of gap gene proteins, which encode transcription factors controlling pair-rule gene expression.
What activates pair-rule genes?
The proteins encoded by the gap genes in turn activate the pair-rule genes. The pair-rules genes are expressed in every other segment and represent the first apparent metameric pattern.
Is engrailed a pair-rule gene?
A well-characterized target of pair-rule function is the segment-polarity gene engrailed (en), which is expressed in 14 stripes during gastrulation and at all subsequent stages of embryogenesis.
What is a gap genes and pair-rule genes?
Gap genes are expressed early in development in broad regions. Pair-rule genes are expressed later in development to define the edges of individual segments. Next, segment polarity genes are expressed even later in development to create polarity within individual segments.
Where is the Nanos gene expressed?
During oogenesis, nanos function is required for the continued production of egg chambers, and nanos is expressed in the early germarium.
What does engrailed gene do?
The engrailed gene is thought to be a ‘selector’ gene that controls the expression of other genes to confer a ‘posterior identity’ on groups of cells that are related to each other by lineage.
Where are gap genes expressed?
embryo
The Gap genes encode transcription factors of the zinc-finger class. They are expressed in relatively broad bands in the embryo, the boundaries of which are “sharpened” by regulatory interactions among the gap genes themselves as well as with the maternal effect genes (see above).
What is the function of a pair rule gene?
A pair-rule gene is a type of gene involved in the development of the segmented embryos of insects. Pair-rule genes are expressed as a result of differing concentrations of gap gene proteins, which encode transcription factors controlling pair-rule gene expression.
What are the bands of expression of pair rule genes?
Pair-rule gene. The bands of expression of the pair-rule genes correspond to the regions missing in the mutant. The expression of the pair-rule genes in bands is dependent both upon direct regulation by the gap genes and on regulatory interactions between the pair-rule genes themselves.
How do gap genes affect pair rule gene expression?
Pair-rule genes are expressed as a result of differing concentrations of gap gene proteins, which encode transcription factors controlling pair-rule gene expression. Pair-rule genes are defined by the effect of a mutation in that gene, which causes the loss of the normal developmental pattern in alternating segments.
What happens when pair-rule genes are absent?
When pair-rule genes are absent, the larva has only half the normal number of segments. The pair-rule proteins then activate the segment polarity genes, a set of genes expressed in a segmentally reiterated manner. Finally, the homeotic genes are activated in a region-specific manner.