Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels

Sanders - Genetic Analysis: An Integrated Approach 3rd Edition

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Sanders 3rd Edition

Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels

Problem 1b

Chapter 20, Problem 1b

Compare and contrast the terms in each of the following pairs:
Random mating and Inbreeding

Verified step by step guidance

Understand the concept of random mating: Random mating occurs when individuals in a population pair by chance, without any preference for genetic traits or relatedness. This ensures that all alleles have an equal chance of being passed on to the next generation.

Understand the concept of inbreeding: Inbreeding refers to mating between individuals who are genetically related, such as close relatives. This increases the probability of homozygosity (having two identical alleles for a gene) and can lead to the expression of recessive traits.

Compare the genetic diversity: Random mating promotes genetic diversity within a population because it allows for a wide mixing of alleles. In contrast, inbreeding reduces genetic diversity and increases the likelihood of genetic disorders due to the expression of deleterious recessive alleles.

Analyze the impact on allele frequencies: Random mating does not alter allele frequencies in a population, as it follows the Hardy-Weinberg equilibrium. Inbreeding, however, can lead to changes in genotype frequencies, increasing homozygosity and reducing heterozygosity.

Consider evolutionary implications: Random mating supports a healthy gene pool and adaptability in changing environments. Inbreeding, while sometimes used intentionally in selective breeding, can lead to inbreeding depression, where reduced genetic diversity negatively impacts survival and reproduction.

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Key Concepts

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

Random Mating

Random mating refers to a mating system where individuals pair without regard to their genotypes or phenotypes. This process promotes genetic diversity within a population, as it allows for a wide range of genetic combinations. In random mating, all individuals have an equal chance of mating, which helps maintain a balanced gene pool and reduces the likelihood of genetic disorders.

Inbreeding

Inbreeding is the mating of closely related individuals, which can lead to a higher probability of offspring inheriting identical alleles from both parents. This practice can reduce genetic diversity and increase the risk of genetic disorders due to the expression of deleterious recessive alleles. Inbreeding can be detrimental to population health, leading to inbreeding depression, where the fitness of the population declines.

Genetic Diversity

Genetic diversity refers to the total number of genetic characteristics in the genetic makeup of a species. It is crucial for the adaptability and survival of populations, as it allows for a greater range of traits that can respond to environmental changes. High genetic diversity is typically associated with random mating, while inbreeding tends to decrease genetic diversity, making populations more vulnerable to diseases and environmental shifts.

Compare and contrast the terms in each of the following pairs:Random mating and Inbreeding