key term - Genetic variance

Definition

Genetic variance refers to the diversity of alleles and genotypes within a population, contributing to the variation in traits among individuals. This concept is crucial for understanding how traits are inherited and how populations adapt to their environments over time. Genetic variance plays a significant role in natural selection, as it provides the raw material for evolution by enabling some individuals to possess advantageous traits that can lead to greater reproductive success.

5 Must Know Facts For Your Next Test

1. Genetic variance can arise from mutations, gene flow, and sexual reproduction, all of which contribute to the diversity seen in populations.
2. High levels of genetic variance in a population can enhance its ability to adapt to changing environmental conditions and resist diseases.
3. Genetic variance is measured using metrics like heritability, which assesses the proportion of phenotypic variance attributable to genetic factors.
4. Population genetics studies the distribution and changes in genetic variance within populations over time, helping to understand evolutionary processes.
5. Inbreeding can reduce genetic variance by increasing homozygosity, potentially leading to inbreeding depression where harmful alleles become more prevalent.

Review Questions

• How does genetic variance contribute to natural selection within a population?
  • Genetic variance provides the essential diversity in alleles that allows natural selection to act on a population. When environmental pressures favor certain traits, individuals with advantageous alleles are more likely to survive and reproduce, passing those traits on to future generations. This process leads to changes in the frequency of alleles over time, illustrating how genetic variance is critical for adaptation and evolution.
• Discuss the implications of low genetic variance on a population's ability to adapt to environmental changes.
  • Low genetic variance can significantly hinder a population's adaptability to environmental changes. With fewer alleles present, there are limited traits available that may confer survival advantages under new conditions. This lack of diversity increases the risk of extinction, as the population may not possess the necessary genetic tools to cope with challenges like climate change or disease outbreaks.
• Evaluate the role of genetic variance in shaping evolutionary dynamics and its importance in conservation biology.
  • Genetic variance plays a pivotal role in shaping evolutionary dynamics by influencing how populations respond to natural selection and environmental changes. In conservation biology, maintaining genetic diversity is crucial for preserving species resilience against threats like habitat loss and climate change. Conservation strategies often aim to enhance genetic variance through habitat corridors or breeding programs, ensuring populations have the adaptive potential necessary for long-term survival.

Related terms

allele: An allele is a variant form of a gene that can produce different traits in an organism.

genotype: A genotype is the genetic constitution of an individual, determining specific traits or characteristics.

phenotypic variance: Phenotypic variance is the observable variation in a trait among individuals in a population, resulting from both genetic and environmental influences.