Should I continue studying OpenGL or just switch to DirectX to give me a better chance of landing a job in the game industry?

I've been learning graphics programming for some time now using OpenGL and Linux. I'm pretty familiar with most of the concepts, but I would really like to further my knowledge and eventually pursue a career in game development, especially game engine development.

So far it seems to me that the majority of game studios make games for Windows using DirectX.

Edit: I know that the OpenGL vs DirectX question has been asked here before, but I haven't found an answer in the perspective I want.

Edit 2: After reading all the responses/comments I've decided to continue diving deeper into graphics with OpenGL/GLSL, but I'll try to play around with DX as well, just to have a basic understanding of the API. I'd like to thank everyone for the answers and insight you've given me.

Answer

It really doesn't matter. The core concepts are the same in both, especially now that pixel shaders are the norm. And since most games are multiplatform they're probably going to use a subset of features that are similar in both languages. As long as you can write shaders in glsl or hlsl, you'll be fine.

That being said, the number of "game engine development" positions out there are small. Most companies use something off the shelf. For those positions that exist, even fewer of them are entry level. Most entry level game programmers don't write any graphics-related code (other than maybe shaders) because it's all been abstracted away.