Answer the questions in the space box **Introduction**Meet Tasha, a boxer dog (Figure 1). In 2005, scientists used Tasha’s DNA to obtain the first complete dog genome sequence, which contains 2.4 billion pairs of nucleotides over 39 pairs of chromosomes! Genome sequence data like this is useful for many reasons; in this activity, you’ll see how this data is used to find genes associated with different traits, such as fur color in dogs. The approach you’ll learn about is called a genome-wide association study (GWAS), and it can be used to learn about the genes of any organism, not just dogs.**Part 1: Introduction to GWAS**Read the information below to learn more about GWAS and its applications, then answer the questions that follow.**What Is GWAS?**GWAS is a method for identifying the genes associated with an organism’s collection of traits, or phenotype. It involves searching the genomes of many individuals — for example, many different dogs — to find DNA differences, or variations, associated with particular traits and phenotypes. After sequencing Tasha’s genomes, scientists sequenced and compared the genes of many dogs from a variety of breeds. They found millions of common variations among these genomes. Some of these variations were associated with the color, length, or texture of a dog’s fur. You’ll learn more about these variations later in this activity.1. In general, why do you think GWAS is useful? What kinds of problems could GWAS be used to solve?**What Are SNPs?**The variations found in GWAS are usually common variations in DNA sequences called single nucleotide polymorphisms, or SNPs (pronounced “snips”). A SNP is a variation in a single nucleotide, at a particular position in the genome, that occurs in over 1% of the population. Different variations of a SNP may be called SNP variants or alleles. Figure 2 shows two alleles for a common SNP in dogs.As shown in Figure 2, SNPs are labeled based on the chromosome they are found on (e.g., chromosome 37, which is abbreviated as Ch37) and their “nucleotide position” (e.g., 25,734,258), which is determined by counting from one end of the chromosome to the other. For the SNP shown in Figure 2, dogs may have either a C or an A. These two versions of the SNP are called the C allele **Mapping Genes to Traits in Dogs Using SNPs****Artificial Selection and Dog Breeding:**Artificial selection, at the heart of breeding for desirable traits in domesticated animals, has resulted in rapid changes in the canine species. Modern dog breeds, diverging from wolves about 15,000 years ago, exhibit genetic changes that breeders have pursued over the last 200 years. Short-haired breeds, like the beagle, display fewer wolf-like codes identified in the study.Modern dogs have a unique population structure due to selective breeding. Researchers analyzed the coat, breaking down complex phenotypes into simpler genetic variations. By organizing these coat varieties, researchers can study complex traits and conditions similar to human diseases.*Excerpt from a National Institutes of Health (NIH) News Release published August 27, 2009.***Questions for Comprehension:**5. How many genes contribute to the diversity of coat types in dogs?6. In two or three sentences, describe how scientists identified these genes.7. Why is it important to analyze the DNA of numerous dogs in this research?8. Humans have SNPs too. How could GWAS studies with dogs benefit humans?**PART 2: Applying GWAS to Dog Fur Color**Let's examine how GWAS (Genome-Wide Association Studies) works using a comparison between dogs with black fur and those with white fur. Table 1 illustrates the SNP alleles at 17 specific genomic locations. Each SNP allele is represented by two nucleotides from parental chromosomes.**Table 1: SNP Alleles in Dogs with Black and White Fur**- 17 loci display combinations of nucleotides from dogs with black fur (first four rows) and dogs with white fur (last four rows).A SNP frequently found in dogs with specific colored fur suggests its association with color. **Questions:**9. Suggest two reasons why a SNP might be linked to a trait like fur color.10. Identify which SNP in Table 1 is fully associated with fur color. Explain.11. Identify which SNPs are completely unassociated with fur color. Explain.12. After Question 10, which SNP has the next strongest association with fur color? Explain.*Updated November 2020* The dataset is part of a student handout designed to teach mapping genes to traits using SNPs, with a focus on understanding genetic associations with physical attributes in dogs.

The branch of Biological Sciences that deals with the study of genome is known as Genomics. The…

Answered: 1. In general, why do you think GWAS is…

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...