Is it normal that i've hated my sister almost my entire life?

When I was 10 months old, my mum had my sickly, 2 months prem sister who required a lot of attention so apparently I got none after that. Her health eventually got good but we never got along because she was always had such a nasty little mouth. When my gorgeous little brother was born, she tormented him and thirty years later, he still says he's traumatised by it. She rang up my husband 12 years ago when he was still my new boyfriend and abused him based on false rumours and gossip. She even admits that her boyfriends have described her as the nastiest person they've ever met. She had a baby with a man who wasn't her husband at the time, but went back to her husband so he could bring up the baby. He suffered from depression because she cheated on him with her boss and flaunted the affair. He ended up having to leave his job because he was no longer functional. He then had no income so of course she left him. (She's a lawyer and thought he wasn't good enough for her. Her son much prefers Daddy, of course, and doesn't realise that his Daddy isn't biological.) Her new husband of only 3 months is a doctor. At the wedding, (which we flew to Bali to attend), she insulted me in front of everyone, which only made her sound like a bitch. Her new husband gave a speech at their last party describing how she'd abused him for the past week, non-stop, trying to get the house perfect for the guests. My grandmother was the same; snapped at everyone, forcing them to walk on eggshells constantly to appease her. Is it genetic? After 46 years, I've had enough. I've decided to cut ties with my sister forever. No more Xmas or birthdays.