Although Patrick’s plan is similar in some respects to California’s enormous $3 billion stem-cell effort and New York’s proposed $1 billion investment in stem-cell and related research, it differs in key respects. The most significant may be that Patrick isn’t billing the effort primarily as a stem-cell plan, even though it’s clear that the state initiative would give the stem-cell field a major boost.

The Massachusetts plan would devote roughly half its total funding to capital investment in research facilities across the state — in part, simply to ensure the wide availability of expensive research equipment for use in stem-cell work. (In California, by contrast, only about 10 percent of the $3 billion can be directed to “bricks and mortar.”) Currently, instruments purchased under a federal grant can only be used in studies involving a limited number of stem-cell lines, a restriction that has hampered the work outside of privately-funded laboratories.

According to this piece in the Boston Globe, another $250 million in the Massachusetts plan will be devoted to direct research grants — a much smaller amount than in other states. The remainder of the $1 billion will consist of tax subsidies designed to draw biotechnology firms to the state. Among the individual projects the plan may subsidize are a tissue bank for housing newly created lines of stem cells and a center for the exploration of a gene-silencing technique called RNA interference that earned a University of Massachusetts scientist the Nobel Prize last year.

Also unlike proponents of the similar plans in California and New York, Patrick isn’t promoting this initiative specifically as a way to cure deadly diseases or to boost economic development in the state. Instead, he casts it as an effort to meet competitive challenges from foreign nations and other states, as well as a way to counter a recent flattening in biomedical research funding through the National Institutes of Health, which has disproportionately affected states like Massachusetts.

The NYT has more here, and notes that the plan also includes $250 million in hoped-for private-sector “matching funds” that will pay for grants, fellowships and capital investment. You can also check out the state’s official press release, a more detailed outline and five-point plan, and even the video of the governor’s announcement.