DATA AVAILABILITY
Fastq files corresponding to small RNA-sequencing libraries are available from the European Nucleotide Archive: ERR12176799 BA1_E10.5_Rep1, ERR12176800 BA2_E10.5_Rep1, ERR12176801 PBA_E10.5_Rep1, ERR12176802 BA1_E10.5_Rep2, ERR12176803 BA2_E10.5_Rep2, ERR12176804 PBA_E10.5_Rep2, ERR12176805 BA1_E11.5_Rep1, ERR12176806 BA2_E11.5_Rep1, ERR12176807 PBA_E11.5_Rep1, ERR12176808 BA1_E11.5_Rep2, ERR12176809 BA2_E11.5_Rep2, ERR12176810 PBA_E11.5_Rep2.