Do some nocturnal primates and bats see in colour?

2009 REU Intern Austin Hicks


Junior Molecular Biology major at Loyola University

REU Mentors: Dr. Robert Martin (A. Watson Armour III Curator of Biological Anthropology, Anthropology) and Edna Davion (Graduate Student, Anthropology)

Symposium Presentation Title: Do Hipposiderid Bats See in Color? (Chordata: Mammalia: Chiroptera: Rhinolophidae)

Symposium Presentation Abstract: Until recently, nocturnal mammals were believed to have a retina that consisted purely of rods, optimized for vision in low light conditions. These rod cells contain the photopigment rhodopsin (RH1) that responds to a single photon of light. Recent studies regarding nocturnal mammals have shown that some, including three groups of primates and some bats have not one, but two different types of cones. Contained in these cone cells are photopigments that are sensitive to light in the blue to yellow (short) wavelengths (SWS1), or to light in the green to red (medium- to long) wavelengths (M/LWS). Cones are therefore the first step in facilitating color vision. Hipposideros is a wide spread micro-bat that consists of approximately 55 species, all of which are nocturnal and insectivorous. The answer we seek is whether Hipposideros has the capacity for color vision. To answer this question, we attempted to sequence the autosomal SWS1- and X-linked M/LWS-opsin genes in Hipposideros. These attempts will be discussed. After sequences have been obtained, we wish to 1) establish if the SWS1 gene is functional, 2) conduct statistical analyses on the SWS1 and M/LWS opsin sequences to test for evidence of purifying, negative or neutral selective pressure on the genes, and 3) analyze these sequences in a phylogenetic context in order to draw inferences regarding the ancestral condition at various nodes in the mammalian tree of life.

Original Project Description: It is generally accepted that the ancestral mammal was nocturnal. Scientists assumed that nocturnal mammals, including some primates, remained nocturnal. This assumption predicted that nocturnal mammals had a pure rod retina. Surprisingly, studies determined that cones were present in the eyes of many nocturnal mammals. Scientists were further surprised by the discovery that some bats and some nocturnal primates had two sets of photopigment genes in addition to the rhodopsin found in rods i.e. the genetic capacity for dichromatic (colour) vision. Using DNA from primates and bats collected from Madagascar and the Phillippines, we will explore this idea in a phylogenetic context.

Research methods and techniques: Interns will receive training and participate in, DNA extraction, PCR, and sequencing in the Museum’s core genetics facility, the Pritzker Laboratory and the DNA Discovery Center. In addition, they will participate in data collection, assembly and analysis.