design: DNA extraction and amplification were performed using a commercial kit (Repli-G Single Cell; Qiagen, Hilden, Germany). Purified DNA was normalized at 20 ng/l and sent to an external laboratory (Genewiz; Azenta Life Sciences; South Plainfield, NJ) where a 150-bp paired-end exome sequencing on an Illumina HiSeq 2500 platform was performed, as previously described (33). Quality controls of each sample were performed by quantitative polymerase chain reaction, and poor-quality nucleotides were removed (error rate <0.01).