Print Singular Genomics, a San Diego startup that’s developing next-generation sequencing technology for oncology and immunology, has filed a prospectus to become a publicly traded company. Founded in 2016, Singular hasn’t disclosed yet how much money it hopes to raise or the proposed price range of its shares. That information should be revealed as Singular gets closer to pricing its initial public stock offering. But it is attempting an IPO at a time when investors are receptive to betting on early stage companies. There have been 141 IPOs priced globally so far this year, up more than 300 percent from the same period last year, according to Renaissance Capital, an IPO investment advisory firm. San Diego-based TuSimple, which is developing self-driving semi-truck technology, recently raised $1 billion in an IPO.