Sample Demographics.

<p>Ethnic group “Others” included 5 Hispanics- and 5 individuals of more than one race.</p

Genotype- and Allele- Frequencies in Sample Populations.

<p><b><u>Abbreviations:</u></b> AA-African-American (N = 33), CE-Caucasians (N = 52), others-(N = 10); MAF-minor allele frequency, HWE- Hardy-Weinberg equilibrium.</p><p>Three AA individuals (9%) and one CE (2%) carry rare 3-UTR alleles.</p

The DAT binding potential in the human brain.

<p>Brain images of dopamine transporter (DAT) availability obtained using [¹¹C]cocaine at the levels where the striatum (left image) and cerebellum (right image) are located. A rainbow color scale is used to represent DAT availability (red>yellow>green>blue>purple. Images are averaged from brains of 20 healthy participants. Note the high DAT levels in striatum (white arrow) and the minimal levels in cerebellum (red arrow).</p

Relationships between the <i>SLC6A3</i> variations and regional DAT measures.

<p><b>Abbreviations</b>: ROI – region of interest; Ventral Str. – ventral striatum.</p><p>Significance level for overall effect of the genotypes (three-genotypes classification) and haplotypes (four haplotypes classification) was set at <i>p</i><0.05 (ANCOVA); values<0.05 are marked with*.</p

Genotype distribution in AA and CE populations.

<p>The height of the bars representing 3′-UTR genotypes (A) and intron8 genotypes (B) corresponds to occurrence of each genotype category (actual number of individuals) in groups comprising African-Americans (AA), Caucasians (CE) and other ethnicity (others).</p

Regression coefficients of DAT availability and age in genotype groups.

<p><b><u>Abbreviations:</u></b><i>b</i>-(beta weights), standardized coefficient; <i>p</i>-significance, values<0.05 are marked with*; <i>t</i>-score (t-statistic is the coefficient divided by its standard error), significant at ItI>2.</p

Increased recombination rate in the VNTR-encompassing regions of the <i>SLC6A3</i> locus.

<p>Both VNTR regions are within the recombination Hotspots indicated by red arrows (HapMap Data Release 27 PhaseII+III, Feb09, on NCBI B36 assembly). The green slashed box encloses a recombination hot spot (upper panel) that is projected to the intron8 (green arrow, bottom panel); the blue dotted box encloses a recombination hot spot (upper panel) mapped to the 3′UTR – region (green arrow).</p

Measures of DAT availability (Bmax/KD) in genotype groups.

<p>Bars correspond to mean DAT availability and standard errors of means in 3′-UTR-genotype (A), intron8-genotype (B) and haplotype groups (C) in <i>caudate</i>, <i>putamen</i> and <i>ventral striatum</i>. Significant differences between the mean values are indicated (p<0.05). Bmax/KD values (Y-axis) correspond to DAT binding potential.</p

Age-related changes in the DAT binding potential.

<p>Scatterplots show the regression between the measures of DAT availability in striatum (Y-axis) and age (X-axis) in 3′-UTR- (A) and intron8-(B) genotype-based groups. Black regression line – all subjects of the sample, colored lines – genotype-based subgroups.</p

Genotype - DAT measures relationships in populations.

<p><b>Abbreviations</b>: ROI – region of interest; Vent. Str. – ventral striatum; AA- African-Americans, CE- Caucasians,</p><p>Significant values are indicated with *.</p