That is, some very good pathogen fighting genes. Some of us are lucky. Others not so much. I think I have neanderthal genes in me - at least that's what everyone says.
The useful gift was the introduction of new variants of immune system genes called the HLA class-1 genes, which are critical for our body’s ability to recognize and destroy pathogens. HLA genes are some of the most variable and adaptable genes in our genome, in part because the rapid evolution of viruses demands flexibility on the part of our immune system.