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.
The months January, February, March and April have nice weather with a good average temperature. On average, the temperatures are always high. Most rainfall (rainy season) is seen in June, July, August, September and October. Puerto Vallarta has dry periods in February, March, April, May, November and December. On average, the warmest month is August. On average, the coolest month is January. September is the wettest month. This month should be avoided if you don't like too much rain. April is the driest month.