The recent mapping of the Nephila clavipes’ spidroin genome  has caused researchers to rethink much assumed knowledge. We now understand that, at least in N. clavipes: (i) individual spiders express multiple versions of the MaSp genes at different loci, potentially leading to several MaSp1 and MaSp2 proteins appearing in the spun silks, (ii) the different spidroin cassettes and motifs are shared and partitioned among the different proteins, and (iii) other spidroins, e.g. AcSps, appear in the major ampullate gland, so can provide additional cassettes and motifs that may form components of MA silk . For these reasons, MA silk amino acid compositions may not necessarily reflect the MaSp1: MaSp2 expression, possibly explaining why nanostructure formations can vary within individual spider silks independent of MaSp1: MaSp2 expression [25–27].