Fig. 2

a Schematic and b partial genomic sequence of the CpG island in the promoter region of ADRB3 ranging from − 988 to − 608 bp (GenBank accession number DQ104441.1). The CpG site studied is presented. Primer regions are indicated by arrows (solid for methylated sequence and dashed for non-methylated sequence). Horizontal bar—CpG island; vertical bars—CpG sites. c Bands of positive (methylated) and negative (unmethylated) control DNA, showing specific amplification for methylated and unmethylated conditions after polymerase chain reaction (109 bp). d Bands of representative samples of the three conditions found in the study population: hypermethylation, hypomethylation, and partial methylation. Partially methylated DNA refers to the amplified samples for methylated and unmethylated conditions indicating that methylation does not occur in all cells or alleles. L- DNA ladder; M methylated, U unmethylated, PC positive control, NC negative control