The full length sequence of the mouse Zp2 gene in BAC RP23-6513 is modified by replacing the corresponding human exons encoding amino acids 41-68 (bp 26 in exon 2 to bp 21 in exon 6) for the mouse amino acids 37-165 (bp 59 in exon 2 to bp 6 in exon 5) at the N-terminus of gene. (J:215794)