Fig. 6
ETSTY7 horizontal transfer between horse/equids and Parascaris. a Maximum likelihood tree for 73 ETSTY7 and ETSTY7-like equid and Parascaris sequences (blue boxes) (sequence data Supplementary Data 7); copies verified to have originated from eMSY (red font) and sequences derived directly from horse and parasite samples noted; BS—bootstrap replicates; b HT validation by PCR using gDNA samples originating from 13 Parascaris individuals, tissues and developmental stages, C. elegans as negative invertebrate control, and male and female horses; Parascaris photo by R. Juras; primers represent the putative HT region (ETSTY7-3 exon3), Parascaris-specific sequences (PEQ001.2), and three multicopy horse-specific sequences - mtDNA (ND1), olfactory receptor genes in chr14 (Chr14 CNV OR), and a CNV in chrUn (ChrUn CNV); 100 bp ladder (NEB); c ETSTY7-3 exon3 612 bp PCR amplicons from Parascaris individuals, tissues and developmental stages that were used for Sanger sequencing; d Reverse transcriptase PCR (RT-PCR) with ETSTY7 primers on a panel of 9 adult equine tissues showing testis-specific expression; e–f FISH with 612-bp ETSTY7-3 PCR product in horse sex chromosomes (red FISH signals in e) and metaphase spreads of donkey and two zebra species (green FISH signals in f); scale bars 1 µm; equid images purchased from Bigstock (https://www.bigstockphoto.com/), and g PCR with ETSTY7-3ex3 primers in equids, Perissodactyls and unrelated diverse mammals showing that these sequences are limited to equids; M male; F female (see Supplementary Data 11 for primer information and Supplementary Note 6 and Supplementary Fig. 8 for more HT validation)
