Large Gene Families

A third major molecular recognition system for 5-HT are the transporter proteins. Transporters consist of 12 membrane spanning proteins and represent a large gene family encoding Na+ and Cl dependent transport proteins. For 5-HT, the first transporter was identified in rat in 1991 [18,19]. The human 5-HT... 

Smadja C, Shi P, Butlin RK, Robertson HM. Large gene family expansion and adaptive evolution for odorant and gustatory receptors in the pea aphid, Ac5Uthosiphon pisum. Mol Biol Evol. 2009 26 2073-86. 

At this writing, a significant amount of work has been undertaken and more is under way utilizing genomic approaches. Thus, for example, the oxidation of tyrosine (Tyr, Y), to dihydroxyphenylalanine is well established across a variety of plant bases and the subsequent decarboxylation of tyrosine (Tyr, Y) to tyramine as well as the oxidation of phenylalanine (Phe, F) to 3,4-dihydroxyphenylalanine (dopa) and its subsequent decarboxylation to 3,4-dihydroxyphenethylamine (dopamine), while catalyzed by different enzymes, involves processes that occur in members of a large gene family all of which are in the opium poppy. ... 

Herbicide selectivity in crops may involve a three-step process of detoxification, conjugation and transport into the vacuole. These three processes can be induced in a coordinated fashion by safeners. The major detoxifying enzymes occur in large gene families, which results in considerable variation in selectivity patterns. Our understanding of these enzymes and their regulation has been greatly assisted by new molecular techniques. 

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