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 Weather. Puerto Vallarta is one of the most naturally beautiful places on earth, and Vallarta's weather can be described as tropically perfect. The weather in Puerto Vallarta is astonishingly nice boasting 322 days of sunshine each year, with warm and sunny days and cool and comfortable nights.