5 Surprising Examples Of Incomplete Dominance In Nature

If you've ever learned about Mendelian genetics in school, you might remember the idea of dominant and recessive traits. However, not all inheritance patterns follow this straightforward rule. Incomplete dominance is a type of genetic inheritance where neither allele for a particular trait is fully dominant over the other, leading to a blending of traits in the offspring. Here are five surprising examples from the natural world where incomplete dominance is clearly at play.

🌺 Four O'Clock Flowers

The Four O'Clock flower, known scientifically as Mirabilis jalapa, exhibits one of the most classic cases of incomplete dominance:

• Red flowers and white flowers are homozygous for their respective color alleles.
• When these flowers cross-pollinate, the resultant offspring display a pink color, which is a blend of both red and white pigments.

<div style="text-align: center;"> <img src="https://tse1.mm.bing.net/th?q=four o clock flower" alt="Four O'Clock Flowers"> </div>

🦊 Silver Foxes

Not widely known, but an interesting example, is the coat color of silver foxes:

• Traditional fox fur can be either red or black, determined by the genotype of the animal.
• When a red fox mates with a black fox, their offspring can sometimes exhibit silver or blue coloration, which is a blend of the two parental colors.

<div style="text-align: center;"> <img src="https://tse1.mm.bing.net/th?q=silver fox" alt="Silver Foxes"> </div>

<p class="pro-note">🐾 Note: Silver foxes were selectively bred by Russian scientists for temperament and fur color, which inadvertently provided insight into incomplete dominance.</p>

🍫 Brown Eggs vs. White Eggs

Egg color in chickens is another fascinating example of incomplete dominance:

• Chickens laying white eggs and those laying brown eggs possess different alleles for egg color.
• When crossed, the result can be speckled or a lighter shade of brown, demonstrating the blended trait.

<div style="text-align: center;"> <img src="https://tse1.mm.bing.net/th?q=chicken eggs color" alt="Chicken Eggs"> </div>

🦜 Budgerigar Parakeets

Budgies, or budgerigar parakeets, have an interesting twist to their feather colors:

• The blue and green colors in Budgies result from an interplay between yellow pigment (melanin) and the absence of blue pigment (structural coloration).
• When mating blue Budgies with green ones, the progeny can exhibit turquoise coloring, which represents an incomplete dominance of the blue over the green.

<div style="text-align: center;"> <img src="https://tse1.mm.bing.net/th?q=budgerigar parakeets" alt="Budgerigar Parakeets"> </div>

🗾 Japanese Cherry Blossoms

Finally, let's turn to a floral example:

• Pink cherry blossoms are an intermediate result when a white cherry tree (with a recessive allele) is crossed with a deep red cherry tree (homozygous for the red color).
• The beautiful pink blossoms of many Japanese Cherry trees are due to incomplete dominance between these two color alleles.

<div style="text-align: center;"> <img src="https://tse1.mm.bing.net/th?q=Japanese cherry blossom" alt="Japanese Cherry Blossoms"> </div>

Conclusion

Nature often doesn't conform to neat genetic categories, and incomplete dominance is just one of many mechanisms through which genetic diversity manifests. From the gentle hues of cherry blossoms to the surprising coat colors of foxes, these examples remind us of the complexity and beauty in the genetic makeup of species. Understanding these genetic interactions not only enhances our appreciation for biodiversity but also helps in the selective breeding of plants and animals for desired traits.

<div class="faq-section"> <div class="faq-container"> <div class="faq-item"> <div class="faq-question"> <h3>What is incomplete dominance?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>Incomplete dominance occurs when neither allele of a gene pair is completely dominant over the other, leading to a phenotype that is a blend or intermediate of the two.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>How can you tell if a trait shows incomplete dominance?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>A trait shows incomplete dominance when offspring exhibit characteristics not seen in either parent, like a mixed or intermediate color or phenotype.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>Are there any practical applications of incomplete dominance?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>Yes, selective breeding in horticulture and agriculture uses incomplete dominance to produce plants and animals with desirable traits, such as the color of flowers, fruits, and eggs.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>Can incomplete dominance occur in humans?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>Yes, though less common, it can occur. An example is hair texture where wavy hair can result from one parent having straight hair and the other having curly hair.</p> </div> </div> <div class="faq-item"> <div class="faq-question"> <h3>Is incomplete dominance the same as co-dominance?</h3> <span class="faq-toggle">+</span> </div> <div class="faq-answer"> <p>No, in co-dominance, both alleles are expressed equally, whereas in incomplete dominance, the phenotype is a mix or intermediate between the two.</p> </div> </div> </div> </div>