Transcription Factors Are Proteins That Bind Specific DNA Sequences to Regulate

Transcription factors are proteins that bind specific DNA sequences to regulate gene transcription.Some families of transcription factors bind zinc molecules to form structural motifs called zinc fingers, which facilitate binding to the DNA.Transcription factors that have the so-called classical zinc finger motif bind each zinc molecule via two cysteine and two histidine amino acids.When comparing the orthologs of these genes in closely related species, one would expect to find that the position and conservation of the cysteine and histidine amino acids in the compared sequences are

A) under neutral selective processes.
B) subject to genetic drift.
C) under positive selection.
D) under purifying selection.
E) highly variant.