Transcriptome Analysis of Early Reproductive Tract Development in the Turkey Using RNA-Seq

Transcriptomic analysis of the turkey reproductive tract is important in understanding development and evolution of the reproductive system.  Analysis of molecular signaling is critical for identification of genes affecting fertility, a key factor in the poultry industry.  In this study, we investigated the transcriptional profiles associated with early development of reproductive tissues in the domesticated turkey using RNA-Seq.  Gonads were collected from 4 males and 4 females at 14 and 28 days of age.  Total RNA was extracted and RNA-Seq libraries were prepared and sequenced on an Illumina HiSeq 1000 (101-cycle single-end).  After trimming and filtering, approximately 248M sequencing reads remained with 125M reads from ovaries and 123M reads from testes.  Total reads were assembled and clustered using a combination of Velvet/Oases suite and PASA using the newly updated turkey genome build (Ver. 5.0), resulting in 24,716 and 23,261 clusters for females and males, respectively.  The results of HTSeq/DESeq showed that 14,440 clusters in females and 13,796 clusters in males are constitutively expressed between D14 and D28, with approximately 3% of clusters being uniquely differentially expressed on D28 in both females and males.  Between genders, over 87% of clusters were constitutively expressed in both testes and ovaries.  Ovaries exhibited higher numbers (1,887 and 1,710 clusters on D14 and D28, respectively) of uniquely expressed clusters than those of testes (728 and 1,072 clusters on D14 and D28, respectively).  This comprehensive overview of gene expression will provide detailed insight into transcriptomic changes of reproductive tract development in young turkeys.