The use of restriction enzymes as a tool for recombining, or joining, different DNA fragments was first illustrated in yet another classic paper, this time by Stanford University researchers Janet Mertz and Ronald Davis (Mertz & Davis, 1972).
Averages for Puerto Vallarta in February. The temperatures are still very warm in Puerto Vallarta, Mexico, in February, even though itâs still winter. Thanks to the cityâs location close to the equator, it enjoys good weather all year round providing the perfect place to head for a winter beach break â it certainly beats the cold European winter.
Puerto Vallarta International Sports Classic (May) Historic Center Art Walk (October to May) July-September: Puerto Vallarta's temperatures spike the most in summer, and there are often brief bursts of rain. Airfare and hotel rates are usually at their cheapest, so pack an umbrella and enjoy the discounts. Key Events: Charro Day (September 14)