PhD or not, Dr Mike Yeadon's gone off the deep end. Here are the bits of the spike protein that show some level of similarity to syncytin-1:
That's... not homologous. These are just the little chance "similarities" you'll see if you attempt to align just about any large protein with any other. The idea that they're problematic is just ridiculous - for quite a few reasons. The biggest:
1) Let's start with the obvious one. If it were actually a problem, then we'd see the exact same problem caused by actual infection by SARS-CoV-2 - after all, the spike protein is the bit that the virus "shows" to the world, that the vast majority of the immune response is raised against.
2) If chance similarities like this were actually able to trigger auto-immune reactions, then we'd all already be dead. The first few infections we picked up after birth would have triggered an unholy storm of auto-immune reactions against just about every protein in our bodies. In reality, a key feature of all our immune systems is the active filtering and removal of all antibodies recognising "self" proteins, and the cells that produce them.
