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Reverse transcription - PCR was then used to clone from human poly ( A ) + RNA the cDNA corresponding to the expressed homolog of psi ARF 4 , referred to as human ARF 4 .
 psi ARF 4, human ARF 4
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 psi ARF 4, human ARF 4