How are recessive trait inherited?

Answer 1

What is the relationship between dominant and recessive traits?

Think of it this way--

A dominant gene will suppress the expression of a recessive gene.

A dominant trait is the expressed result of an organism having either one dominant and one recessive gene for that trait, OR two dominant genes for that trait. For example, brown eye color is normally dominant over blue.

A recessive trait is the expressed result of having two recessive genes. For example, you need two recessive genes to get blue eyes.

Each parent contributes one gene for each trait. If a parent carries a recessive gene for blue and a dominant gene for brown, that parent will have brown eyes, but can contribute either gene to a child. If the other parent has the same, the child could have two brown eyed parents but have blue eyes.

Eye color is a visible trait, but each gene location can be or contribute to a trait not visible to the eye. For example, the genetic disposition to ovarian cancer is not something we can see without genetic testing.

A recessive gene can be inherited and remain silent for generations, waiting to pair up with another recessive to be expressed. The knowledge that this does occur is one of the reasons why genetic testing is recommended before having children. There are so-called lethal genes that are recessive and only become problematic when they meet up with another.

I know I have simplified things here, but I hope that gets to the core of your question. I recommended taking a look at the OMIM.org website to appreciate how complex this really is. That the unraveling of the miracle of the human genome has been accomplished during the last decade is truly wonderful.

Answer 2

Imagine there are two genes which decide the exact same trait.

We will call the dominant gene P, and the recessive gene Q.

Dominant means that if both genes are present, then only the dominant gene will take effect.

Recessive is the opposite of Dominant.

Okay, so a couple conceive a child, one partner has two P genes for the particular trait, and the other partner has two Q genes.

There is one possible outcome for the genes of their child.

If each parent gives 1 gene, the outcome would be PQ, as the father can only give P, and the mother can only give Q.

Therefore as P is the dominant gene, the child will have the same trait as it;s father.

However, when that child is old enough to have a child of it's own, it carries both P and Q genes, either of which can be present in a sperm or egg cell.

If the child's partner also has the genes PQ for the trait, ther are 4 possible outcomes for the baby they will have together.

They will be : PP, PQ, QP, QQ

This means that there is a one in four chance of the baby inheriting it's grandmothers trait, of QQ.

The other three options are all going to be option P, as the P gene is dominant.

Answer 3

First of all alleles code for different traits all across an organism. Simply looking at it, a dominant allele is a trait that essentially "dominates" or is expressed over a recessive allele. In theory every organism (that is not asexual) receives one allele from its father and one allele from its mother. If both of these alleles are dominant (homozygous dominant) than the dominant trait is expressed, if one is dominant and one is recessive (heterozygous) than still the dominant trait is expressed. However, if the alleles for both traits are recessive (homozygous recessive) than the recessive trait will be expressed.

Answer 4

A recessive trait can only be passed along if both parents carry at least one of the recessive genes to the child. If both parents manifest the trait (that is, if both parents have both recessive genes), then the child will manifest (that is, carry both recessive genes and display) the recessive trait. If one parent manifests and the other parent only carries the trait (that is, carries one dominant and one recessive gene) then the child will definitely carry and have a 50% chance of manifesting. If both parents carry the recessive, the child is 25% likely not to carry the trait at all, 50% likely to carry and 25% likely to manifest the trait.

Answer 5

In order for a recessive trait to be seen in an organism, the organism needs two copies of the gene that codes for that particular trait. A dominant trait only requires one gene to be present., as that one gene would code for enough of the protein to overpower the other recessive gene present.

Answer 6

because when you have and dominant and recessive trait the dominant we always show up