A cline is a gradual change in the frequency of an allele or trait across a geographic area. This change can be influenced by various factors like:
* Natural selection: Different environments can favor different alleles.
* Gene flow: The movement of individuals between populations can introduce new alleles and change allele frequencies.
* Genetic drift: Random fluctuations in allele frequencies can occur, especially in smaller populations.
Clines are often observed in populations that are adapted to different environments or that have experienced different levels of gene flow.
