dominant lethal

Examples of dominant lethal in the following topics:

• Lethal Inheritance Patterns

  • In other instances, the recessive lethal allele might also exhibit a dominant (but not lethal) phenotype in the heterozygote.
  • The dominant lethal inheritance pattern is one in which an allele is lethal both in the homozygote and the heterozygote; this allele can only be transmitted if the lethality phenotype occurs after reproductive age.
  • Individuals with mutations that result in dominant lethal alleles fail to survive even in the heterozygote form.
  • Dominant lethal alleles are very rare because, as you might expect, the allele only lasts one generation and is not transmitted.
  • However, just as the recessive lethal allele might not immediately manifest the phenotype of death, dominant lethal alleles also might not be expressed until adulthood.

• Plant Defenses Against Pathogens

  • Many metabolites are toxic and can even be lethal to animals that ingest them.

• Mendel's Law of Dominance

  • Rather than both alleles contributing to a phenotype, the dominant allele will be expressed exclusively.
  • It is sometimes convenient to talk about the trait corresponding to the dominant allele as the dominant trait and the trait corresponding to the hidden allele as the recessive trait.
  • For example, to say that "green peas" dominate "yellow peas" confuses inherited genotypes and expressed phenotypes.
  • Dominance is not inherent.
  • One allele can be dominant to a second allele, recessive to a third allele, and codominant to a fourth.

• Alternatives to Dominance and Recessiveness

  • The variant may be recessive or dominant to the wild-type allele.
  • In cases of multiple alleles, dominance hierarchies can exist.
  • In this case, the wild-type allele is dominant over all the others, chinchilla is incompletely dominant over Himalayan and albino, and Himalayan is dominant over albino.
  • These pink flowers of a heterozygote snapdragon result from incomplete dominance.
  • Discuss incomplete dominance, codominance, and multiple alleles as alternatives to dominance and recessiveness

• Excitation–Contraction Coupling

  • A lethal exposure to Sarin can cause death within one minute.

• Genetic Variation

  • 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.

• Plant Defenses Against Herbivores

  • Many metabolites are toxic and can even be lethal to animals that ingest them.

• Disorders in Chromosome Number

  • Monosomy for autosomes is usually lethal in humans and other animals.

• Life Cycles of Sexually Reproducing Organisms

  • The main categories of sexual life cycles in eukaryotic organisms are: diploid-dominant, haploid-dominant, and alternation of generations.
  • There are three main categories of life cycles in eukaryotic organisms: diploid-dominant, haploid-dominant, and alternation of generations.
  • Within haploid-dominant life cycles, the multicellular haploid stage is the most obvious life stage.
  • The third life-cycle type, employed by some algae and all plants, is a blend of the haploid-dominant and diploid-dominant extremes.
  • Fungi, such as black bread mold (Rhizopus nigricans), have haploid-dominant life cycles.

• The Punnett Square Approach for a Monohybrid Cross

  • The dominant seed color is yellow; therefore, the parental genotypes were YY (homozygous dominant) for the plants with yellow seeds and yy (homozygous recessive) for the plants with green seeds, respectively.
  • If the pattern of inheritance (dominant or recessive) is known, the phenotypic ratios can be inferred as well.
  • In a test cross, the dominant-expressing organism is crossed with an organism that is homozygous recessive for the same characteristic.
  • If the dominant-expressing organism is a homozygote, then all F1 offspring will be heterozygotes expressing the dominant trait.
  • A test cross can be performed to determine whether an organism expressing a dominant trait is a homozygote or a heterozygote.