What is dominant trait and examples

Dominant traits refer to traits or characteristics that will appear or stand out in an organism if these traits are inherited from both parents. In inheritance, there are two types of traits, namely dominant traits and recessive traits.

If a dominant trait is inherited from both parents, then the dominant trait will appear in the organism. For example, if the dominant trait is black hair, then if both parents have black hair, their children will also tend to have black hair.

However, if a dominant trait is inherited by only one parent, while the other has a recessive trait, then the dominant trait will still appear in the organism. For example, if the dominant trait is black hair and the recessive trait is blonde hair, and one parent has black hair and the other has blonde hair, then their child will have black hair.

In genetics, dominant traits are indicated using capital letters, while recessive traits are indicated using lowercase letters. For example, if H is the dominant trait for height and h is the recessive trait for height, then individuals with the HH or Hh genotype will have tall height, while individuals with the hh genotype will have short height.

So, a dominant trait is a trait or characteristic that will appear or stand out in an organism if the trait is inherited from both parents.

What’s that

Dominant traits are traits that dominate or control other alleles in a pair of alleles at a genetic locus. Dominant traits will always be manifested (visible) when an individual has one dominant allele in their partner, whether they are dominant homozygotes (AA) or heterozygotes (Aa).

Definition of Dominant Traits

A dominant trait is a trait that is controlled by a gene that is expressed in the presence of one or two copies of the gene. This means that an individual who inherits one copy of the gene for a dominant trait will express that trait, regardless of whether they inherit a second copy of the gene.

Dominant traits are often represented by uppercase letters, such as “A” or “B”. This is because the trait is expressed even if only one copy of the gene is present.

Example:

Suppose there are two alleles for plant seed color: the red allele (R) and the yellow allele (r). Red seed color is a dominant trait, while yellow is a recessive trait.

  • If an individual has the R allele from the father and the r allele from the mother (heterozygous Rr), then the visible color of the seeds is red.
  • If an individual has the R allele from the father and the R allele from the mother (homozygous dominant RR), then the visible color of the seeds remains red.
  • Only if an individual has both r recessive alleles from both (homozygous recessive rr), then the visible color of the seeds is yellow.

Thus, a dominant trait (for example red seed color) will appear even with the presence of only one dominant allele in the allele pair.

1. Attached Ear Lobes

Attached ear lobes is a dominant trait that is controlled by a gene on chromosome 12. An individual who inherits one copy of the gene for attached ear lobes will have attached ear lobes, regardless of whether they inherit a second copy of the gene.

2. Widow’s Peak

A widow’s peak is a dominant trait that is controlled by a gene on chromosome 20. An individual who inherits one copy of the gene for a widow’s peak will have a widow’s peak, regardless of whether they inherit a second copy of the gene.

3. Hitchhiker’s Thumb

A hitchhiker’s thumb is a dominant trait that is controlled by a gene on chromosome 11. An individual who inherits one copy of the gene for a hitchhiker’s thumb will have a thumb that is capable of being bent backwards, regardless of whether they inherit a second copy of the gene.

Conclusion

In conclusion, dominant traits are traits that are expressed in an individual even if only one copy of the gene for that trait is present. Dominant traits are often represented by uppercase letters, and there are many examples of dominant traits in genetics. Understanding dominant traits is important for understanding how traits are inherited and expressed in offspring.

FAQs about Dominant Traits

What is a dominant trait?

A dominant trait refers to a genetic characteristic or phenotype that is expressed when an individual has at least one copy of the corresponding dominant allele. It masks the expression of a recessive allele when present in a heterozygous genotype. Dominant traits are often represented by uppercase letters in genetic notation.

How are dominant traits inherited?

Dominant traits are inherited following the principles of Mendelian genetics. If an individual inherits at least one copy of the dominant allele, they will express the dominant trait. Dominant alleles are represented by capital letters (e.g., “A”), while recessive alleles are represented by lowercase letters (e.g., “a”). Dominant traits can be inherited from either one or both parents, depending on the specific inheritance pattern.

What is the difference between dominant and recessive traits?

The main difference between dominant and recessive traits lies in their expression in individuals with different genotypes. Dominant traits are expressed when an individual has at least one copy of the dominant allele, even if they also have the recessive allele. In contrast, recessive traits are only expressed when an individual has two copies of the recessive allele (homozygous recessive genotype).

Can dominant traits skip generations?

Yes, dominant traits can appear to skip generations. This can happen when individuals who possess the dominant trait pass it on to their offspring, who may not express the trait but can carry the dominant allele as a heterozygous genotype. In subsequent generations, when individuals with the heterozygous genotype reproduce with other carriers or individuals expressing the trait, the dominant trait can reappear.

Are dominant traits more common than recessive traits?

The frequency of dominant and recessive traits in a population can vary and is not inherently determined by the dominance or recessiveness of the alleles. Dominant traits can be more common in a population if the dominant allele has a higher frequency or provides a selective advantage. However, the prevalence of dominant and recessive traits depends on multiple factors, including genetic variation, gene flow, and natural selection.

Can a dominant trait be harmful?

Yes, a dominant trait can be harmful. While dominant traits are often associated with visible and apparent characteristics, they can also be linked to genetic disorders or negative health outcomes. Some dominant genetic disorders, such as Huntington’s disease, are caused by mutations in dominant alleles. In such cases, inheriting a single copy of the mutated dominant allele can lead to the development of the disorder. It is important to note that not all dominant traits are harmful, and many play essential roles in normal physiological functions.

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