Many labs, including mine, welcome postdocs with expertise in a more or less different field, but it's a riskier move - PIs need to consider every hire as an investment of finite time and resources, and PDs need to think of how to be productive & happy. Some thoughts: [thread]
PD candidates switching fields, make sure you know: 1) Why do you want to do this? Why this specific lab? Wanting to e.g. "learn computational skills" is not enough - labs need PDs who're interested in their research program, and PDs need to be excited about their research topic.
2) How will you be productive? Which of your skills are immediately applicable? Do you have an excellent track record of being a fast learner? It's a difficult sell if you ask a PI to spend ~$100K into you just learning but not producing, and you need papers the faster the better
Everyone involved should think of the structure of PD work particularly carefully for PDs switching fields. I've found it helpful start with a smaller, more technical project to learn the data types - then they can move to bigger biological questions (often with great success).
Being able to switch fields is something that should be encouraged and enabled - it adds to career flexibility, and is super valuable for science by enhancing interdisciplinary work. So successful transitions are important! [/end]
