The results of SNP genotyping in nine stickleback fish populations with reduced or absent pelvises (source locations shown in Figure B). Triangles indicate SNP markers that were used to identify the approximate location of deletion mutations. Dark blue bars indicate that the SNP markers on both sides of that section were present, thus that section of DNA was present. Light blue bars indicate that only one of the two SNP markers on either side of the section was present, meaning that the deletion started somewhere in that section. Light gray horizontal bars indicate that both SNP markers on each side of that section were missing, meaning that the section of DNA was wholly deleted. Three sequences, 4, 6, and 7, were sequenced completely and the length of the deletions are indicated to the right. Red bars indicate the location of two noncoding regions (Pel-2.5-kb and Pel-501-bp), based on DNA constructs from marine fish, which are able to drive gene expression specifically in the pelvis. The gray-shaded vertical rectangle indicates the 488-bp region where all the deletions overlap, which includes SNP markers indicated in red.
Project or distribute the image to engage students. The downloadable Educator Materials PDF includes background information, graph interpretation and discussion questions. The Student Handout includes the image and background information.
Figure 4A & 4B from:
Chan, Y. F., et al. (2010). Adaptive Evolution of Pelvic Reduction in Sticklebacks by Recurrent Deletion of a Pitx1 Enhancer. Science, 327(5963), 302–305.