Ectodysplasin-A receptor(Edar)was firstly found in mammal, and plays vital roles in developmental events of the skin appendages. The screening for transcripts of skin from jian carp and mirror carp by Genefishing differential found Edar is one of the targeted different expressed in both materials, and the partial fragment of Edar gene was recovered from differential expressed products by sequencing. Then by cloning, the mirror carp Edar CDS consisted of 1 389 base pair nucleotides which encodes a 462 amino acid protein, has a signal peptide, a tumor necrosis factor receptor region, a transmembrane region and death domain. The alignment result showed that the carp shares the highest similarity(88.31%)with the zebrafish. However, it has the relative lower similarity with Xenopus laevis (64.88%)chicken(63.79%), human(64.36%), mouse(63.50%)due to evolutionarily distant relationships. The 5'-UTR shares the high variation, even with the medaka(24.73%)and zebrafish(23.78%). Also, in the 3'-UTR, it varies significantly with medaka(35.49%), let alone with Xenopus laevis (11.73% and 9.42%), human(6.50% and 8.05%), mouse(10.04% and 10.04%). The in situ results showed that the Edar unique expression signal was detected in skin matrix which the scale formed, but weak or no expression signal was detected in other positions on skin, later disappeared in full developed scaled body. All of these results showed that this gene may involve the initiation of the scales not the maintenance of the scale pattern formation.
