incomplete dominance

(noun)

a condition in which the phenotype of the heterozygous genotype is distinct from and often intermediate to the phenotypes of the homozygous genotypes

Related Terms

Examples of incomplete dominance in the following topics:

  • Alternatives to Dominance and Recessiveness

    • With the inclusion of incomplete dominance, codominance, multiple alleles, and mutant alleles, the inheritance of traits is complex process.
    • The allele for red flowers is incompletely dominant over the allele for white flowers.
    • 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

  • Gaps in the Fossil Record

    • Because not all animals have bodies which fossilize easily, the fossil record is considered incomplete.

  • 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.

  • Animal Reproduction and Development

    • Some animals, such as grasshoppers, undergo incomplete metamorphosis, in which the young resemble the adult.
    • Regardless of whether a species undergoes complete or incomplete metamorphosis, the series of developmental stages of the embryo remains largely the same for most members of the animal kingdom.
    • (a) The grasshopper undergoes incomplete metamorphosis.

  • 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.

  • Lethal Inheritance Patterns

    • In other instances, the recessive lethal allele might also exhibit a dominant (but not lethal) phenotype in the heterozygote.
    • 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.
    • People who are heterozygous for the dominant Huntington allele (Hh) will inevitably develop the fatal disease.
    • Huntington's disease occurs when an abnormal dominant allele for the Huntington gene is present.

  • Transferring of Energy between Trophic Levels

    • Assimilation is the biomass (energy content generated per unit area) of the present trophic level after accounting for the energy lost due to incomplete ingestion of food, energy used for respiration, and energy lost as waste.
    • Incomplete ingestion refers to the fact that some consumers eat only a part of their food.

  • 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.

  • Movement and Migration

    • Additionally, in some animals, only a portion of the population migrates, whereas the rest does not migrate (incomplete migration).

  • Fungi Habitat, Decomposition, and Recycling

    • The food web would be incomplete without organisms that decompose organic matter .