Final answer:
The phenomenon of difference in allele frequencies and gene expression in wet and dry environments is primarily studied in the subdiscipline of population genetics (option 1). Translation is a separate process in genetics.
Step-by-step explanation:
The phenomenon of 1) difference in allele frequencies in wet and dry environments and 2) difference in gene expression in wet and dry environments are primarily studied in the subdiscipline of population genetics.
Population genetics is a field of science that focuses on understanding how allele frequencies change within populations over time, including the impact of environmental factors.
This subdiscipline explores the forces of evolution at the level of allele frequencies in populations and investigates how different alleles and environmental factors contribute to phenotypic variation.
Translation is the process by which the genetic code in a sequence of messenger RNA (mRNA) is decoded to produce a specific sequence of amino acids, which ultimately leads to the synthesis of proteins.
While translation is an essential process in genetics, it is not specifically associated with the phenomena mentioned in the question.