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Fig. 9 | Genome Biology

Fig. 9

From: Rapid divergence of a gamete recognition gene promoted macroevolution of Eutheria

Fig. 9

Species diversity of Zan amino acid sequence and processing. A. Taxon-specific variation in proteolytic processing sites of the zonadhesin precursor. Asp-Pro bonds (“DP,” downward arrows) cleaved during the proteolytic processing of the pig zonadhesin precursor [123] are widely conserved among mammalian taxa in the D2 and D4 VWD domains (panels D2, D4), but the D1 domain site is not conserved in myomorph rodents (panel D1). Numbers denote amino acid positions of the consensus sequence downstream of the alignment’s start at the D0 domain. Note the P→L/V substitution, driven by positive selection (sites denoted by asterisks), in all 11 myomorph species, but conservation of P in the others. Note also in the rodent species the downstream amino acid substitutions in D1 as well as the substitutions both upstream and downstream of the cleaved DP in D4, also driven by positive selection, reflecting the accelerated divergence of Zan in these animals. B. Species heterogeneity of zonadhesin D3 and D3p domain polypeptides. Shown are western blots of resolved sperm proteins from nine species, representing Orders Rodentia, Lagomorpha, Carnivora, Perissodactyla, Cetartiodactyla, and Primates, probed as indicated with affinity-purified antibody to the mouse zonadhesin D3 VWD domain (anti-muD3) or the D3p18 partial VWD domain (anti-muD3p18). Migration of size markers (Mr × 10−3) is indicated on the left. Species abbreviations are as follows: Mu, mouse; Rt, Norway rat; Ha, Syrian hamster; GP, guinea pig; Rb, rabbit; Dg, dog; Eq, horse; Po, pig; Hu, human. Note with anti-muD3 the detection of the well-characterized Mr 105,000 zonadhesin D3 polypeptides of porcine and equine spermatozoa [90, 124, 125], the detection of similarly sized D3 polypeptides in human, dog, and rabbit spermatozoa, and the detection of multiple larger polypeptides in rodent spermatozoa. Note with anti-muD3p18 the detection only in the three species of myomorph rodents of high Mr D3p18 immunoreactivity (>160,000 Mr), including the well-characterized Mr 300,000 polypeptide of mouse and hamster spermatozoa [62, 126]

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