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.
Weather lowdown. Although December is technically winter in Puerto Vallarta, Mexico, the weather is still extremely mild thanks to the city's positioning so close to the equator. The month is characterised by long, sun-filled days and minimal rainfall â the perfect time to visit to catch some winter sun.