Inheritance
Complete Dominance
Complete dominance is when the dominant allele is shown over the recessive. Either the alleles are heterozygous (some for dominant and recessive) or the alleles are homozygous (all dominant). Looking at the picture to the left the first three outcomes show complete dominance.
Incomplete Dominance
Incomplete dominance is when one allele for a specific trait is not completely dominant over the other allele which results in a combined phenotype. The best example of this are from the snapdragons when they were crossed-breed with red and white alleles resulting in the mixture of the colors making pink snapdragons.
Co-Dominance
Co-dominance is when both alleles in a heterozygous situation are completely expressed that makes a phenotype that is neither dominant nor recessive. For example the blood type AB, the person has both A and B alleles resulting in the blood type AB which are both dominant (co-dominance).
Punnet Squares
Punnet squares are a good tool that we can use to help understand and predict the inheritance of particular traits. The most common type of punnet square is a a 2X2 punnet square but they can be used up to as many as you need to predict the likelihood of certain traits. On the top and sides of the square you put the genotypes of the trait to predict the genotype offspring will have. The example of the punnet square to the left shows the genetic contribution of the parents, one parent on the left side and the other parent on the top of the punnet square. Yellow is the dominant gene and green is the recessive gene. The red shows the genotypes that the offspring "could" end up with. The offspring has a 25% chance to be homozygous yellow, 50% heterozygous yellow and 25% homozygous green.
Pedigrees
Pedigrees are yet another method to show inheritance. In a pedigree circle are representative of females and squares for males. As you move from top to bottom is show the offspring of the parents and generations.
Autosomal-Is the chromosomes other than the sex chromosomes or genes on the chromosomes. These chromosomes is a way to determine wither or not a trait, disease or disorder can be passed on. Autosomal recessive means the carrier has two copies of abnormal genes to allow the trait to show up. Autosomal dominant means you only need one copies of the gene for it to show in your traits.
X-Linked- Female are XX so with sex-linked genotypes they do not show the symptoms of certain traits but carry it instead. Males are XY, so when a certain sex-linked trait is present they show the symptoms.
Dominant- Means only one of the one allele for the phenotype to show through.
Recessive- Means you need two of the recessive alleles for the phenotype to show through.
Autosomal-Is the chromosomes other than the sex chromosomes or genes on the chromosomes. These chromosomes is a way to determine wither or not a trait, disease or disorder can be passed on. Autosomal recessive means the carrier has two copies of abnormal genes to allow the trait to show up. Autosomal dominant means you only need one copies of the gene for it to show in your traits.
X-Linked- Female are XX so with sex-linked genotypes they do not show the symptoms of certain traits but carry it instead. Males are XY, so when a certain sex-linked trait is present they show the symptoms.
Dominant- Means only one of the one allele for the phenotype to show through.
Recessive- Means you need two of the recessive alleles for the phenotype to show through.
Resources
http://www.biology-online.org/dictionary/Complete_dominance
http://biology.about.com/od/geneticsglossary/g/incompletedom.htm
http://www.biology-online.org/dictionary/Codominance
http://anthro.palomar.edu/mendel/mendel_2.htm
http://www.biotopics.co.uk/genes/pedigr.html
http://www.umm.edu/ency/article/002049.htm
http://biology.about.com/od/geneticsglossary/g/incompletedom.htm
http://www.biology-online.org/dictionary/Codominance
http://anthro.palomar.edu/mendel/mendel_2.htm
http://www.biotopics.co.uk/genes/pedigr.html
http://www.umm.edu/ency/article/002049.htm