In all animals, changes in access to food during growth affects final adult size; greater nutrition produces larger adults. However, not all parts of an organism grow at the same rate, and so changes in access to nutrition during growth can affect the ultimate size of different parts of the body differently. Although the effects of nutritional variation on relative trait size are well documented, only recently have the tools become available to (i) enable study of how genetic and developmental mechanisms manage the growth of traits to produce a properly proportioned adult and to (ii) enable study of how these mechanisms change to alter growth patterns to produce size diversity among species. Here, the investigators will take a novel approach by changing diet in lines of fruit flies, each possessing their own unique and known genetic code, to identify the specific genes underlying the regulation and integration of growth among various parts of the body. This research will be coupled with a new, fun elementary school computer-based learning activity where students will alter the relative growth of structures in virtual creatures, transforming young humans into fantastical beings.
Phenotypic plasticity is the ability of a genotype to express different phenotypes across environments. It is well studied on a phenomenological level, particularly for morphological traits; phenotypic plasticity can hinder or promote adaptation, lead to the genesis of evolutionary novelties or serve as an adaptation itself. A lack of experimental tools has meant that two components central to the evolution of morphological plasticity - the variation among individuals in the expression of plastic responses and the proximate bases of this variation - are essentially unknown. Nutritionally-induced size variation is common to all metazoans: nutritional limitation during ontogeny generally produces smaller individuals than does a nutritionally rich diet, although the degree of nutritionally-induced size plasticity can vary dramatically among morphological traits. Such differences in relative trait plasticity are rooted in recently identified developmental genetic mechanisms that regulate and integrate the growth of traits in response to nutritional variation. Frankino (PI) and Shingleton (co-PI) hypothesize that variation in these same mechanisms underlies the evolutionarily important variation among genotypes in trait plasticity. Here, they propose to test this hypothesis by: (i) applying new methods to create and quantify the among-individual variation in nutritionally-induced trait and body size plasticities; (ii) using genome-wide association mapping to identify genes that contribute to this variation, and; (iii) employing a series of developmental assays to confirm the role of these genes in producing among-individual variation in nutritionally induced size plasticity.
