I work for a start-up software company transitioning to Scrum. We don't have dedicated positions yet, so I'm wondering what kind of repercussions (negative and positive) could come about if one person played the role of QA lead and product owner?
As a Product Owner my role is to be forward thinking and prioritize the Product backlog so that the development team is always working on the most important issues and have enough detail about what is comming down the pipe.
Generally the PO is someone from the Marketing Department, the visionary that knows what the product needs to do and when it needs to do it.
As a QA lead, my role is to focus on the current iteration and engage with the development team as early as possible to facilitate that the code will be testable and that the test that can be automated are.
While there is not a direct conflict of interest they are both full time jobs that would be difficult to do by one person.
depending on the size of your company, you did say start up, it might be practical to gather your stakeholders (the people generating the stories, Marketing, Biz Dev, Sustainment) and have a product owners group. I have seen this work, but there is one very important caviate, someone needs to have ultimate authority as to what is the most important issue. That can be a rotating position made up of the stakeholders or someone they all report to.
I think there could be a conflict of interest: As Product Owner you would be focusing of development and implementation, and may wish to cut corners to get new features of the product delivered. On the other hand, in the QA role you may find that you need to stop the development, or at least slow it down to allow quality issues to be resolved. Unless you are very good at segmenting your mind, you will compromise one or other of the roles - or possibly even both if you end up trying to avoid any internal conflict.
I would take a different tack. One person should take on the Product Owner role, and another person could pick up the QA role. It may be possible to combine these roles with some other suitable roles within the company where there is less conflict of interest. Even if this means providing some extra training for a couple of people, I reckon it would pay dividends, and in a start-up, I would hope that the people involved would be prepared to expand their horizons to take on new skills.