genetic diversity

Examples of genetic diversity in the following topics:

• Types of Biodiversity

  • Genetic diversity, ecosystem diversity, and human-derived diversity are measures of biodiversity that currently define life on earth.
  • Genetic diversity is one of those alternate concepts.
  • Genetic diversity or variation is the raw material for adaptation in a species.
  • A genus with very different types of species will have more genetic diversity than a genus with species that look alike and have similar ecologies.
  • Genetic diversity can be measured as chemical diversity in that different species produce a variety of chemicals in their cells, both the proteins as well as the products and by-products of metabolism.

• Genetic Variation

  • Genetic variation is a measure of the variation that exists in the genetic makeup of individuals within population.
  • Genetic variation is a measure of the genetic differences that exist within a population.
  • The genetic variation of an entire species is often called genetic diversity.
  • Because wild cheetahs are threatened, their species has a very low genetic diversity.
  • This low genetic diversity means they are often susceptible to disease and often pass on lethal recessive mutations; only about 5% of cheetahs survive to adulthood.

• Pollination and Fertilization

  • Plants can transfer pollen through self-pollination; however, the preferred method is cross-pollination, which maintains genetic diversity.
  • Genetic diversity is, therefore, required so that in changing environmental or stress conditions, some of the progeny can survive.
  • Self-pollination leads to the production of plants with less genetic diversity since genetic material from the same plant is used to form gametes and, eventually, the zygote.
  • In contrast, cross-pollination leads to greater genetic diversity because the male and female gametophytes are derived from different plants.
  • Because cross-pollination allows for more genetic diversity, plants have developed many ways to avoid self-pollination.

• The Species Concept in Microbiology

  • The number of species of bacteria and archaea is surprisingly small, despite their early evolution, genetic, and ecological diversity.
  • The approximately 5000 species of bacteria and archaea constitute a surprisingly small number, considering their relatively early evolution, genetic diversity, and ability to reside in all ecosystems on Earth.
  • The most commonly accepted definition is the polyphasic species definition,which takes into account both phenotypic and genetic differences.

• Agricultural Diversity

  • Maintaining genetic biodiversity of wild species of our crops that are related to domesticated species ensures our continued food supply.
  • This crop diversity matched the cultural diversity of highly-subdivided populations of humans.
  • Potatoes are only one example of human-generated diversity.
  • The potato demonstrates a well-known example of the risks of low crop diversity.
  • Maintaining the genetic diversity of wild species related to domesticated species ensures our continued food supply.

• Prokaryotic Reproduction

  • Prokaryotes reproduce asexually by binary fission; they can also exchange genetic material by transformation, transduction, and conjugation.
  • Binary fission does not provide an opportunity for genetic recombination or genetic diversity, but prokaryotes can share genes by three other mechanisms .
  • Archaea are not affected by bacteriophages, but instead have their own viruses that translocate genetic material from one individual to another.
  • This short generation time, coupled with mechanisms of genetic recombination and high rates of mutation, result in the rapid evolution of prokaryotes, allowing them to respond to environmental changes (such as the introduction of an antibiotic) very rapidly.

• Antibody Genes and Diversity

  • Complex genetic mechanisms evolved which allow vertebrate B cells to generate a diverse pool of antibodies from relatively few antibody genes.
  • Several complex genetic mechanisms have evolved that allow vertebrate B cells to generate a diverse pool of antibodies from a relatively small number of antibody genes.
  • This enormous diversity of antibodies allows the immune system to recognize an equally wide variety of antigens.
  • This serves to increase the diversity of the antibody pool and impacts the antibody's antigen-binding affinity.
  • Outline the two stages which result in antibody diversity: somatic (V(D)J) and recombination stages

• The Diversity of Life

  • The diversity of life can be classified within the three major domains (Bacteria, Eukarya and Archaea) using phylogenetic trees.
  • The fact that biology, as a science, has such a broad scope has to do with the tremendous diversity of life on Earth.
  • The source of this diversity is evolution, the process of gradual change during which new species arise from older species.
  • To construct his tree, Woese used genetic relationships rather than similarities based on morphology (shape).
  • Woese's approach was revolutionary because comparisons of physical features are insufficient to differentiate between the prokaryotes that appear fairly similar in spite of their tremendous biochemical diversity and genetic variability.

• Genetic Engineering in Animals

  • The purpose of genetic engineering in animals is to create animals with special characteristics.
  • Scientists are now capable of creating new species of animals by taking genetic material from one, or more, plants or animals, and genetically engineering them into the genes of another animal.
  • Genetically engineered animals are also created to help medical researchers in their quest to find cures for genetic disease, like breast cancer.
  • Finally, endangered animal species can be cloned, thus helping wildlife management in its goals of preserving wild populations of the earth's biological diversity, and by ensuring that endangered animals' genetic information will not be lost when the last of the species dies.
  • Despite this debate, the law in both the United States and in Europe, tends to support genetic engineering research and development by allowing genetically engineered animals to be patented.

• Defining Population Evolution

  • Genetic variation in a population is determined by mutations, natural selection, genetic drift, genetic hitchhiking, and gene flow.
  • Millions of years of evolutionary pressure caused some organisms to died while others survived, leaving earth with the diverse life forms we have today.
  • Within this diversity is unity; for example, all organisms are composed of cells and use DNA.
  • Five forces can cause genetic variation and evolution in a population: mutations, natural selection, genetic drift, genetic hitchhiking, and gene flow.
  • This diversity results from evolution.