Alterations in expression of a cannabinoid receptor (CNR1, CB1), and of fatty acid amide hydrolase (FAAH) that degrades endogenous ligands of CB1, may contribute to the development of addiction. The 385C>A in the FAAH gene and six polymorphisms of CNR1 were genotyped in former heroin addicts and control subjects (247 Caucasians, 161 Hispanics, 179 African Americans and 19 Asians). In Caucasians, long repeats (≥14) of 18087–18131 (TAA)8–17 were associated with heroin addiction (P = 0.0102). Across three ethnicities combined, a highly significant association of long repeats with heroin addiction was found (z = 3.322, P = 0.0009). Point-wise significant associations of allele 1359A (P= 0.006) and genotype 1359AA (P= 0.034) with protection from heroin addiction were found in Caucasians. Also in Caucasians, the genotype pattern, 1359G>A and −6274A>T, was significantly associated with heroin addiction experiment wise (P= 0.0244). No association of FAAH 385C>A with heroin addiction was found in any group studied.

Cultivated maize (Zea mays) and several other members of the Tribe Andropogoneae produce unisexual f lorets. In maize, the formation of two staminate f lorets in each spikelet on the tassel and a single pistillate f loret in each spikelet on the ear includes a pistil abortion process that requires the action of the TASSELSEED2 gene. In Eastern gamagrass (Tripsacum dactyloides) the GYNOMONOECIOUS SEX FORM1 gene appears to perform a similar role in pistil abortion. These genes were shown to be homeologs by restriction fragment length polymorphism mapping and by the failure of the gsf1 and ts2 alleles to complement one another in intergeneric hybrids. Molecular analysis of the gsf1 allele shows that it is caused by a 1.4-kb deletion mutation. Both TASSELSEED2 and GYNOMONOECIOUS SEX FORM1 show similar expression patterns in subepidermal cells of pistils just before abortion. These results suggest that the formation of staminate f lorets in the Andropogoneae represents a monophyletic trait.