Honestly Bella Ramsey played Ellie perfectly. Wasn’t too sure about the casting choice at first but wow!

Oops, oh no I was certainly not referring to 'mutated' genes. I have not played the game so I don't know anything about why Belle is immune.

I was more referring to how our genes are revealed in our unique features, many of which can be seen shared in people. So I innocently and naively said 'The actor's unique features match the uniqueness of her character'.

I was walking past a young kid the other day and looked at their face and had the thought 'wow, I went to a school with someone with the same features and had thought of how they may have a shared gene'. That's where I was coming from added to the idea that often small percentages of a population can be immune to pathogens and it has nothing to do with 'mutated genes' e.g. A small proportion of humans show partial or complete innate resistance to HIV, the virus that causes AIDS. The main mechanism is a mutation of the gene encoding CCR5, which acts as a co-receptor for HIV. 

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