the human blood type is controlled by the gene 'I'. It is of 3 types Ia, Ib and i. the alleles 'Ia' and 'Ib' produce slightly different sugar polymers protruding on its surface while the 'i' doesn't produce any sugar polymers. as humans are haploid the contain 2 alleles out of the 3 I gene alleles, as the individual alleles come from the parent gamete. the alleles 'Ia' and 'Ib' are completely dominant over 'i', i.e, if alleles 'Ia' and 'i' are present then only the allele 'Ia' will be expressed, and the same for 'Ib' and 'i' happens, but when 'Ia' and 'Ib' are present together then they both express their own types, this is because of the co-dominance.
Ia + Ia = IaIa = A
Ia + Ib = IaIb = AB
Ia + i = Iai = A
Ib + Ia = IbIa = AB
Ib + Ib = IbIb = B
Ib + i = Ibi = B
i + i = ii = 0 (zero commonly known as O)
There are three
The word part poly- means "many," and genic refers to genes. Polygenic traits are determined by multiple genes, each contributing a small effect to the overall trait. So, the terms poly- and genic in polygenic traits indicate that multiple genes are involved in determining the trait.
Humans have about 20, 000 to 25,000 genes.
Since we can never be sure that we know everything about the mechanisms behind blood clotting and there may always be just another protein involved in it, there is at the moment no definitive answer to this question. Even if we could be sure that our knowledge is comprehensive, it would still be difficult to define exactly which genes are "for blood clotting" and which aren't, as many genes contribute indirectly to blood clotting. There is however no reason for there to be a difference between males and females in this number. If you are considering only the main clotting factors (tissue factor, VII, X, prothrombin, V, VIII, IX, fibrin and XIII), these are 9 genes.
There are estimated to be 26000 genes after completing the human genome project.
4
Since this is an illegal activity, it is not possible to estimate the population involved.
The genes for the others work in similar fashions, though certainly not all have three alleles. The other aspect of blood type which is of most interest to us is the Rh factor. Genetically, this is much simpler than the ABo system. It has only two alleles, one dominant (Rh-positive) and one recessive (Rh-negative).
The Y chromosome is smaller than the X chromosome and contains fewer genes. It carries the genes necessary for determining male sex and some other genes, but it lacks many of the genes present on the X chromosome. This is why the Y chromosome does not carry any alleles in the same way that the X chromosome does.
The gene you are referring to is called a Hox gene. Hox genes are a class of master control genes that play a critical role in determining the body plan and specifying the identity of body segments during development in many organisms.
It depends on the trait. Some are Mendelian traits where there is one dominant and one recessive allele. Some traits are governed by multiple alleles, like blood groups, and some traits are governed by polygenic inheritance where several sets of genes determine the trait, like height in humans.
No, hereditary information is stored in chromosomes within the cell's nucleus. Ribosomes are responsible for protein synthesis, not storage of genetic information. Each chromosome contains many genes that provide instructions for making specific proteins.