13961
Proerythroblasts and megakaryocytes massively accumulated in the spleens of the heterozygotes , and we showed that the neomycin resistance gene (which is the positive selection marker in ES cells ) was expressed profusely in the abnormally abundant cells generated in the GATA-1.05 mutant females .
 GATA-1.05, megakaryocytes, Proerythroblasts, ES cells, neomycin resistance gene
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 GATA-1.05, megakaryocytes, Proerythroblasts, ES cells, neomycin resistance gene