Complex Pattern Of Inheritance
Multiple Alleles
Traits are controlled by more than two alleles that usually code for a certain characteristic in a species.
There are two possible phenotype's.
The human ABO blood type is a good example of multiple alleles. Humans can have red blood cells that are of type A , type B , or type O . These three different alleles can be combined in different ways following Mendel's Laws of Inheritance
There are two possible phenotype's.
The human ABO blood type is a good example of multiple alleles. Humans can have red blood cells that are of type A , type B , or type O . These three different alleles can be combined in different ways following Mendel's Laws of Inheritance
Incomplete Dominance
Neither gene is dominant over the other.
So, the offspring in heterozygous will result in a new phenotype
So, the offspring in heterozygous will result in a new phenotype
Examples of incomplete dominance are:
A snapdragon flower that is pink as a result of cross-pollination between a red flower and a white flower when neither the white or the red alleles are dominant.
A brown fur coat on a rabbit as a result of one rabbit's red allele and one rabbit's white allele not dominating.
Codominance
Both alleles are expressed.
Offspring that are hetrozygous receive one version of the gene from each parent.
For example
A cow with brown hair and a cow with black hair mate, therefore the offspring has both brown and black hair
If the male has A blood group and the female B blood group then the human offspring might have AB blood group
Offspring that are hetrozygous receive one version of the gene from each parent.
For example
A cow with brown hair and a cow with black hair mate, therefore the offspring has both brown and black hair
If the male has A blood group and the female B blood group then the human offspring might have AB blood group
Polygenic traits
Trait controlled by nonallelic gene.
phenotypes are controlled by multiple genes.
For example
Most polygenetic traits are partially influenced by the environment. For example, height is partially influenced by nutrition in childhood. If a child is genetically programmed to be average height but does not get a proper diet, he or she may be below average in size.
phenotypes are controlled by multiple genes.
For example
Most polygenetic traits are partially influenced by the environment. For example, height is partially influenced by nutrition in childhood. If a child is genetically programmed to be average height but does not get a proper diet, he or she may be below average in size.
sources: www.wikipidea.com