I had been looking forward to reading Origin since I heard about it last year some time. The premise sounded original and really entertaining. And you know what? It truly was. I didn't end up caring for this book very much, but it does have some good things to offer, and I'm going to get those out of the way first.I can tell that Jessica Khoury did lots of research and did it well. She nailed the flora and fauna of the Amazon rain forest and made it come alive. The book was atmospheric and the setting is not one you encounter often. That part of the book was truly a pleasure to read. It was easy to get lost in the book and feel like you were really there with the characters. The beautiful prose helped as well. The thing is, I would have gotten lost in the book even more if I had actually liked the characters and subject matter.I liked ONE character in this book. And the Jaguar. That was it. Pia was unlikable to me. She was naive, weak, and as someone who was supposed to be immortal, I found her pretty pathetic. Eio made a misogynistic statement early on that really pissed me off, and once that happened, there was no redeeming himself (see my Goodreads status update for the comment). Though I do not think he was a bad person, he did nothing for me as a love interest. I didn't believe in the chemistry between Eio and Pia, and I really wish they had remained friends. They were only together for a few scenes before it was true love. I wouldn't call it instalove, but it was pretty damn close. Does there HAVE to be a romance in every young adult book? That's why I enjoy reading YA by male authors sometimes. They usually focus on the story and less on the romance, if there even is one. I also had issues with some of the dialogue. Some of it felt unnatural and really clunky. It wasn't that bad, I just had issues with everyone being SO SERIOUS all the time. Everyone spoke in perfect English, there was never any slang, and I just felt like the characters (except one) were all cardboard cutouts. I was just very underwhelmed. There was no one to root for. Hard to explain, and I know some are enjoying this book, so it could totally be me.I mentioned in my status updates that I would not read this book if you are an animal lover. I still stand by that statement. You will be horrified. There are several scenes of animal torture and testing in Origin. One is in the opening pages, there is one in the middle, and then towards the end, there is one so bad I ended up sobbing and having to skip over most of it. Don't do it to yourself. They were REALLY hard for me to read. And though I understand why they were included in the story, I found them to be too much. Too graphic. And almost as if they were just added for shock value.To top everything all off, I was pretty unimpressed by the ending. I agree with the way the author wrapped things up, I just found the writing and style anticlimactic. I did feel the ending was a little too tidy, though I am not sure there was another way to end it. It was pretty predictable and a little too happy for me. I saw it coming. Sometimes the bittersweet is better. It's not all happily ever after, but most of it is. Ultimately, I was just really unimpressed with this book. I'll be honest, I was expecting a lot, and it just did not live up to the hype. Definitely readable and I made it to the end, but it's not one I can recommend. Though it is getting mixed reviews, so you may want to try it if you are okay with the things I mentioned. I will definitely try this author in the future. She can write, but this book didn't do anything for me.