Under the indicator models of mate choice, female preferences evolve to exploit the condition-dependence or "indicator value" of male traits, which in turn may cause these traits to evolve to elaborate extremes. If the indicator value of a male trait changes, the payoff function of the female preference for that trait should change and the preference should evolve to a new optimum. I tested thi...

It has been well established that carotenoid and melanin pigmentation are often condition-dependent traits in vertebrates. Expression of carotenoid coloration in birds has been shown to reflect pigment intake, food access and parasite load; however, the relative importance of and the potential interactions among these factors have not been previously considered. Moreover, carotenoid and melanin...

DEDICATION To my mom, Christine E. Brown, and my dad, James W. Brown. v ACKNOWLEDGEMENTS Thanks to my committee members, especially my advisor, Ethan D. Clotfelter, for challenging me, straightening me out when I erred, and supporting my work. Thank you for all the times you had to tell me something you knew I wouldn't like, because you helped me improve. Thank you to Sistema Nacional de Areas ...

The relationship between carotenoid accumulation and the expression of carotenoid biosynthetic genes during fruit maturation was investigated in three citrus varieties, Satsuma mandarin (Citrus unshiu Marc.), Valencia orange (Citrus sinensis Osbeck), and Lisbon lemon (Citrus limon Burm.f.). We cloned the cDNAs for phytoene synthase (CitPSY), phytoene desaturase (CitPDS), zeta-carotene (car) des...

Accumulated in large amounts in carrot, carotenoids are an important product quality attribute and therefore a major breeding trait. However, the knowledge of carotenoid accumulation genetic control in this root vegetable is still limited. In order to identify the genetic variants linked to this character, we performed an association mapping study with a candidate gene approach. We developed an...

The temperature dependence of carotenoid synthesis in Neurospora crassa was investigated. The primary light reaction is independent of temperature, but the amount of carotenoid pigment which subsequently accumulates in the dark is strongly dependent on the temperature during the dark incubation. Carotenoid synthesis shows a sensitivity to both high and low temperatures, and of the temperatures ...

Carotenoids are a group of pigments that are essential to human diets. An increasing interest in carotenoids as a nutritional source of vitamin A and health-promoting compounds has prompted the recent progress in metabolic engineering of carotenogenesis in food crops. Current strategies have been mainly focused on manipulating genes encoding carotenogeic enzymes. In many cases, it is difficult ...

The links between appearance and health influence human social interactions and are medically important, yet the facial cues influencing health judgments are unclear, and few studies describe connections to actual health. Increased facial skin yellowness (CIELab b*) and lightness (L*) appear healthy in Caucasian faces, but it is unclear why. Skin yellowness is primarily affected by melanin and ...

The carotenoid biosynthesis genes form a cluster within the genome of Rhodobacter sphaeroides, lying in the middle of a larger cluster and 45 kb in length, which contains genes for bacteriochlorophyll biosynthesis and for the reaction center and light-harvesting apoproteins. The positions and approximate limits of the carotenoid genes were determined previously by localized transposon Tn5 mutag...

Attaining defined steady-state carotenoid levels requires balancing of the rates governing their synthesis and metabolism. Phytoene formation mediated by phytoene synthase (PSY) is rate limiting in the biosynthesis of carotenoids, whereas carotenoid catabolism involves a multitude of nonenzymatic and enzymatic processes. We investigated carotenoid and apocarotenoid formation in Arabidopsis (Ara...