example of incomplete dominant and codominance or dominance
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Answer:
Explanation:
Incomplete dominance is an important concept in the study of genetics. It refers to a circumstance in which the two copies of a gene for a particular trait, or alleles, combine so that neither dominates the other. This creates a new phenotype or set of observable characteristics caused by the interaction of genetics and environment. In short, incomplete dominance is when neither gene is fully dominant, and the result is a brand new trait.
Codominance is a similar yet different phenomenon. While in incomplete dominance, neither allele is dominant, in codominance, both alleles are. As a result, codominant traits are expressed equally in the phenotype; that is, the result is a combination of the two traits. That differs from incomplete dominance, in which the result is something new, as the examples of incomplete dominance below demonstrate.
Observing Incomplete Dominance
It's important to note that most observable traits in any living thing are caused by more than one gene. Incomplete dominance is specific to traits that occur on just one gene. However, there are many such traits, and incomplete dominance occurs in every sort of organism that has genes, including plants, animals and even human beings.
Incomplete Dominance in Animals
Incomplete dominance in animals is most widely studied in domestic animals since it's important for their health, appearance, and value. Here are several examples of the effects of incomplete dominance in animals:
Chickens with blue feathers are an example of incomplete dominance. When a black and a white chicken reproduce and neither allele is completely dominant, the result is a blue-feathered bird.
When a long-furred Angora rabbit and a short-furred Rex rabbit reproduce, the result can be a rabbit with fur longer than a Rex, but shorter than an Angora. That's a classic example of incomplete dominance producing a trait different from either of the parents.
Tail length in dogs is often determined by incomplete dominance. Pups of long-tailed and short-tailed parents often split the difference and have medium-length tails.
On the subject of dogs, lots of labradoodles have wavy hair. Just like humans, that comes from having straight-haired and curly-haired parents. The result is an intermediate inheritance: the wavy-haired labradoodle.
The cream gene in horses is a classic incomplete dominant. When paired with a red allele, the cream allele produces horses with golden coats such as palominos and buckskins.
Incomplete Dominance in Plants
The science of genetics began with plants. People have been interbreeding plants for particular traits since we first started farming more than 11,000 years ago. Gregor Mendel, one of the founders of genetic science, began his studies by recording the ways he planted his garden. Whether for food, other uses, or simple beauty, humans have employed genetic selection of plants, including incomplete dominance, throughout our history.
Incomplete dominance was first recorded in plants. The German scientist Josef Kolreuter bred red and white carnations, expecting to get offspring with the dominant red coloration. Instead, many came up pink! Kolreuter found that neither allele was fully dominant in his flowers and identified the concept of incomplete dominance.
Four-o-clocks are flowering plants that get their funny name from their inclination to bloom in the late afternoon. Wild four-o-clocks tend to have red flowers, while "pure" four-o-clocks with no coloration genes are white. Mixing the two results in pink flowers, just like Dr. Kolreuter's carnations. Those pink flowers are a result of incomplete dominance. However, mixing the pink flowers results in ¼ red, ¼ white and ½ pink. That 1:2:1 ratio - a quarter like one parent, a quarter like the other, and the remaining half different from either - is common in cases of incomplete dominance.