Insertion of a 1.2kb P-element 69bp upstream of the y transcription start site, together with deletion of y sequence from -146bp to -70bp. The P-element is internally deleted, containing 829bp of 5' sequence and 347bp of 3' sequence, with the filler sequence TAGCTACAAA in between. The P-element is transcribed in the opposite orientation to that of the y gene.
Body colour: pigmentation of the body and wings is reduced, pigmentation of thoracic, leg, wing and abdominal bristles is normal.
y2s20 has abnormal body color phenotype, enhanceable by ph-pP1
ph-pP1, y2s20 has wing sensillum phenotype
ph-pP1, y2s20 has prothoracic leg sensillum phenotype
ph-pP1, y2s20 has mesothoracic leg sensillum phenotype
ph-pP1, y2s20 has metathoracic leg sensillum phenotype
ph-pP1, y2s20 has adult abdominal sensillum phenotype