Abstract
Dopamine is the key to our happiness and is a type of neurotransmitter that carries nerve impulses through the brain. Adequate dopamine levels in the body help to regulate mood, attention and learning, and can even affect our personality. Faba bean (Vicia faba L.) is the most popular food in the world, especially the Arab world. In Egypt, it is number one, in addition to its high content of phenylalanine which is the basic precursor for dopamine biosynthesis in human body. The aim of this study is to find out the most faba bean (Vicia faba L.) genotype which contains high levels of phenylalanine. Seeds of four faba bean genotypes (Giza 716, Sakha 1, Sakha 3 and Sakha 4) were planted in open field until fruiting. Faba bean plants were then analyzed using ISSR-PCR and HPLC to find out ISSR markers related to phenylalanine accumulation. Total number of ISSR-PCR bands was (55), out of them (35) bands were polymorphic with 63.6% polymorphism. The highest number of bands (9) was produced by ISSR 07 primer. ISSR 01, ISSR 04 and ISSR 09 primers produced seven (7) bands, while the lowest number of bands was (2) produced by ISSR 08 primer. ISSR 02 primer showed the highest degree of polymorphism (100%), while ISSR 08 primer showed 0.0% of polymorphism. ISSR 07 primer indicated (8) polymorphic bands out of total number of bands (9), with a degree of polymorphism of 88.9%. Total number of marker bands produced was (13), four (4) of them were resulted by primer ISSR 07. The primers ISSR 02 and ISSR 05 indicated two (2) marker bands. On the other hand, primers ISSR 03 and ISSR 08 showed no marker bands. Dendrogram indicated that the studied four genotypes were clustered into two main clusters. The two genotypes Giza 716 and Sakha 1 were grouped in one cluster with a high degree of similarity about 98%. Close similarity between these two genotypes suggests that Sakha 1 may be evolved from Giza 716 during breeding programs. While, the two genotypes Sakha 3 and Sakha 4 were grouped in another cluster with a degree of similarity of about 70%. HPLC analysis indicated that Sakha 3 genotype contained higher amounts of phenylalanine in seed coat, seed cotyledons and pod valves, as compared to other three genotypes (Giza 716, Sakha 1 and Sakha 4). Sakha 3 genotype indicated also the highest number of ISSR marker bands (6) which could be correlated to high accumulation of phenylalanine. Sakha 3 genotype is recommended for human as a good food to maintain high dopamine biosynthesis in human body.

Key words: Dopamine, ISSR markers, Faba bean, HPLC, Phenylalanine.