5779
Activation of the aboral ectoderm - specific Spec2a gene in blastula - stage sea urchin embryos requires an upstream regulatory region that is part of a repetitive sequence element ( RSR ) associated with all Spec1 / Spec2 genes .
 ectoderm - specific Spec2a gene, Spec1, Spec2
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 ectoderm - specific Spec2a gene, Spec1, Spec2