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Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
Chapter 20, Problem 33a

Evaluate the following pedigree, and answer the questions below for individual IV-1. Is IV-1 an inbred individual? If so, who is/are the common ancestor(s)?

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Step 1: Understand the concept of inbreeding. Inbreeding occurs when an individual inherits alleles from ancestors who are related, leading to a higher probability of homozygosity for certain traits. A common ancestor is an individual who appears in the ancestry of both parents of the individual in question.
Step 2: Examine the pedigree chart provided. Identify the parents of individual IV-1 and trace their ancestry back through the generations to determine if they share any common ancestors.
Step 3: Look for any individuals in the pedigree who appear in both the maternal and paternal lines of IV-1's parents. These individuals would be considered common ancestors.
Step 4: If common ancestors are identified, confirm that IV-1 is inbred by verifying that these ancestors contribute genetic material to both sides of IV-1's lineage.
Step 5: Note the names or identifiers of the common ancestors (if any) and ensure you understand how their presence in the pedigree establishes inbreeding for IV-1.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Pedigree Analysis

Pedigree analysis is a method used to trace the inheritance of traits through generations in a family tree format. It helps identify patterns of inheritance, such as autosomal dominant or recessive traits, and can reveal relationships between individuals, including potential inbreeding. Understanding how to read and interpret pedigrees is crucial for evaluating genetic relationships and determining the likelihood of certain traits being passed on.
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Inbreeding

Inbreeding refers to the mating of individuals who are closely related genetically, which can increase the probability of offspring inheriting identical alleles from both parents. This can lead to a higher risk of genetic disorders and reduced genetic diversity. Identifying inbred individuals in a pedigree involves looking for common ancestors and assessing the degree of relatedness between individuals.
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Common Ancestors

Common ancestors are individuals from whom two or more individuals are directly descended. In pedigree analysis, identifying common ancestors is essential for determining inbreeding and understanding genetic relationships. The presence of common ancestors in a pedigree can indicate a shared genetic background, which is a key factor in assessing the potential for inbreeding in a given individual.
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