Question: The Peripheral Nervous System (PNS) Of A New Fly Species Consists Of A Variety Of Sensory Organs, Which Are Composed Of At Least One Neuron And Its Supporting Cells (such As Bristles, Etc.). All Of The Cells Within A Sensory Organ Is Derived From One Sensory Organ Precursor Cell (SOP); However, A Cluster Of Cells Are Competent To Become An SOP, But …

The peripheral nervous system (PNS) of a new fly speciesconsists of a variety of sensory organs, which are composed of atleast one neuron and its supporting cells (such as bristles, etc.).All of the cells within a sensory organ is derived from one sensoryorgan precursor cell (SOP); however, a cluster of cells arecompetent to become an SOP, but within each cluster, only one cellbecomes the SOP. Two types of sensory organs are the externalsensory organs (ESOs) and the internal organs (ISOs). Many genesare involved in PNS development. A subset of these genes is: i)gene 1: Deletion mutations in this gene cause the elimination ofall sensory organs. The epidermis from which the PNS is deriveddevelops normally. The number of progeny of the epidermal cells,however, appears smaller, and the CNS is also reduced. ii) gene 2:Loss-of-function mutations in this gene result in the absence ofESOs. Instead, ISOs develop where ESOs normally develop. iii) gene3: Loss-of- function mutations in gene 3 results in the loss ofESOs. Ectopic expression of gene 3 results in ectopic ESOs. iv)gene 4: Loss-of-function mutations in gene 4 causes an increasednumber of ISOs. Overexpression of gene 4 causes a decreased numberof ISOs. v) gene 5: Loss-of-function mutations in gene 5 result inthe absence of ISOs. Ectopic expression of gene 5 results inectopic ISOs and, in some cases, the conversion of ESOs into ISOs.vi) gene 6: Mutations in gene 6 cause the bristles in the ESOs toform abnormally. A. Order the above genes into a genetic pathway(s)for PNS development in this fly. Justify why you ordered the genesas such. B. How could you test experimentally whether your pathwayis correct? What results would you expect?