Down syndrome is neither dominant nor recessive.
It is "autosomal" or "other"; it is simply an error in the translation process of Chromosome 21 (three copies instead of two). Instead of 46 chromosomes, a person with Down syndrome will have 47.
Diabetes is neither a dominant or recessive disorder its whats known as a polygenic or 'complex' disease and is caused by the contribution of many different genes working together and signals from the environment around your cells such as nutrition or obesity.
No single gene alone causes diabetes but reason diabetes can be seen to be inherited in families is because in these familes there are a high number of risk alleles (different versions of the same gene) being passed on and these alleles cause a higher risk of developing diabetes.
An example of a gene which causes higher risk of diabetes is DBQ1 which encodes a protein present on the cells surface that works with the immune system to prevent the destruction of insulin producing cells in the body. If a person has two copies of the mutant version of the gene they have an 18 times greater risk of developing diabetes than a person who has two unmutated copies of this gene varient.
But this is just a greater risk of developing the disease it does not mean that a person who has these mutant genes will get diabetes.
Diabetes is a very complex disorder and many tens if not hundreds of genes work together to cause it.
Diabetes is the name given to a group of disorders with common symptoms. All involve disturbance to our ability to process glucose.
Some of these disorders have 'loose genetic connections' that reflect primarily a recessive inheritance pattern.
A number can also be shown to have maternal inheritance, suggestive of mitochondrial inheritance.
Yet others express a silent mutation in one of the four genes involved in insulin release when there is overload demand for insulin. These often express as 'mature-onset' or 'Insulin-independent' diabetes.
Finally there is considerable evidence to support the infection theory of diabetes induction, particularly in cases of 'juvenile', also known as 'Insulin-dependent' diabetes. There may be genetic factors responsible for the auto-immune response that triggers the destruction of the pancreas (which tissue produces insulin).
Not surprisingly, you can also acquire insulin-dependent diabetes if you lose your pancreas surgically, either during the removal of a tumor or during attempts to repair damage following a car accident or sporting injury.
It is a recessive trait
A recessive trait cannot be dominant over a dominant trait. Dominant traits are always expressed over recessive traits in heterozygous individuals because they mask the expression of the recessive trait.
A recessive trait. When a recessive allele is with a dominant allele, only the dominanate trait can be seen.
recessive
False. A living thing that shows a dominant trait may be either homozygous dominant (two dominant alleles) or heterozygous (one dominant and one recessive allele) for the trait. It cannot be homozygous recessive for a dominant trait.
An observable trait of an organism that can mask a recessive trait is called a dominant trait. Dominant traits are expressed in the offspring even if they only have one copy of the dominant allele, hiding the recessive trait's expression.
A recessive trait is a characteristic of an organism that can be masked by the dominant form of a trait. It is only expressed when an individual inherits two copies of the recessive allele. Examples include blue eye color being masked by brown eye color.
The weaker trait that can be covered up by the dominant trait is called a recessive trait. It is only expressed when an individual has two copies of the recessive allele.
Recessive traits are not expressed when the dominant form is present. This is because the dominant allele masks the expression of the recessive allele in the heterozygous condition. Only when an individual has two copies of the recessive allele will the recessive trait be expressed.
A recessive trait is a trait that is not dominant, and is not really seen in ones phenotype.
dominant
dominant