distinguish between the terms "dominant" and "recessive" as used in genetics.?

Answer 1

Genes that are dominant trump those that are recessive. For example, if you have a short gene and a tall gene, the tall gene trumps the short gene and you'll be tall. Other examples include eye color. If your parents have different eye colors, the baby will only inherit the dominant eye color. The other eye color would be recessive.

-Kevin

Answer 2

You need 2 genes one from each parent for any trait. In recessive, you need 2 alike for it to show. In dominant 1 will cause the trait to show. They use a capital letter to represent a dominant and a small case letter to represent a recessive.
For eye color. Brown is dominant. It will show if you have BB or Bb. blue is recessive represented by the letter b. bb will be blue.

Answer 3

Let me explain dominance and recessivity in more biological terms for you. So, I'm assuming you understand the concept of meisois, and how humans receive one allele for each gene from his/her mother, and a different allele from his/her father. So for every single gene in your DNA, you have 2 separate copies. Both alleles of virtually all genes are expressed somewhere in the body (with rare exception).

Now, if one copy of a gene is mutated, and one copy is normal (we call this heterozygosity), sometimes this will not have ANY phenotypic effect, i.e. the cell will look and act perfectly normal. This we call a RECESSIVE mutation, because one mutated copy does not affect the phenotype, but TWO mutated alleles of the gene mean NO normal (in genetics we call normal "wild type") protein product would be expressed, and that would make this phenotype expressed RECESSIVELY.

Now, in some genes, in order for there to be proper expression in a cell, there need to be TWO NORMALLY FUNCTIONING ALLELES. This gene we say is expressed DOMINANTLY. Of course if someone is missing both copies of a dominant gene, naturally there will be no protein product expressed.

There are 3 reasons why a person HETEROZYGOUS for a dominant mutation would express a mutant phenotype:

1. Haploinsufficiency - If one allele is mutated, but the 2nd allele is normal, only half the protein product will be made in each cell. In a recessively inherited condition, this would be ok, half of normal protein amounts WOULD BE enough. But in a dominantly inherited condition, half of the protein product is NOT ENOUGH FOR THE WILD TYPE (normal) PHENOTYPE. We call this HAPLOINSUFFICENCY, because a heterozygote (someone who carries 2 different alleles) WILL EXPRESS A MUTANT PHENOTYPE, not the WILD TYPE.

2. Gain of function mutation - This means that in a person who is carrying one normal allele, and one mutated allele, the mutated allele is expressing a product that is CAUSING a certain disease. That means that just one gene copy of this mutation is enough to cause a mutant phenotype. That makes this a form of dominant inheritance.

3. Dominant Negative - This means that in a person who is carrying one normal allele and one mutant allele, that the mutant allele protein product is negatively affecting the NORMAL allele protein product. That means that having just one bad copy of this gene will also express a mutant phenotype.

This might be a little more in depth than high school, or AP biology, but in college, you should understand this.

Answer 4

Dominant allele is the one that determines the organisms appearance. The recessive allele is the one that has no noticeable affect but it gets passed down to the enxt generation and could possible determine the appearance.

Answer 5

dominanat genes are those which suppress the expression of the reccesive gene .a heterozygous pair containing a dominant and recessive allele expresses only the dominant character.the recessive character is expressed only when 2 recessive alleles are present[homozygous recessive]

Answer 6

dominant in genetics means that the character will appear in the person with only one gene of the character
recessive means that the character will not appear unless it is paired,i.e 2 genes of it
for example
a gene of brown eye is dominant has a symbol B
a gene of blue eye is recessive has a symbol b
a person who has the gene BB or Bb has brown eyes
but the person whose gene both are small bb is blue eyes