While investigating a gene that might be responsible for pathogen resistance in the plant Arabidopsis, you discover that many of the nucleotides in the gene sequence are methylated. Which nucleotide is MOST likely to be methylated

Cytosine nucleotides

Explanation:

In most organisms, the methylation of DNA exists in three different sequence motifs. These include: CG (or CpG), CHG or CHH (H represent A, T or C). In plants, cytosine can be methylated at CpG, CpHpG, and CpHpH regions (H represents any of these nucleotide A, T or C except guanine. DNA methylation is almost majorly found in CpG dinucleotides, with the cytosines on both strands usually always being methylated in mammals.