They believe that it is billions of microevolution mutations in the genome, creating new alleles, and natural selection preserving those changes that is the process of evolution.
Mendel’s ideas were based on careful experimentation and showed that individual characteristics were surprisingly resilient and constant. Each is a complex and precise process that has much biochemical signaling and purpose.
In reality there are multiple mutation processes that can impact a genome but evolutionists only choose one. There are tens of maybe hundreds or trillions of combinations in our genome to recombine. The type of mutations called point mutations are the only genetic processes that can actually add information to the genome and that is why evolutionists have chosen point mutations as the mutational driver of evolution.
We will hereafter call point mutations simply mutations to simplify the writing.
Genetics and evolution have been enemies from the beginning.
Gregor Mendel and Charles Darwin were contemporaries.