why is "O" blood the most common type of blood?
449038
Dominance and recessive have nothing to do with frequency of an allele.  Basically, O is recessive because if you have an A allele and an O allele you will have type A blood, and if you have a B allele and an O allele you will have type B blood.  However, O is the most common type because most people don't have an A or a B allele, but just two O's.  The fact that A or B will be expressed if you have one doesn't make it more likely that you will have one.\n\nA and B are co-dominant (that's where the AB bloodtype comes from), but O is recessive to both A and B as it does not appear in the phenotype if an A or B allele is present.  Incidentally, these alleles are typically denoted I superscript A for A, I superscript B for B, and i for O, which reflects the dominance pattern as capital letters typically indicant dominant and lowercase indicate recessive.
55332
Blood in the human body is both red and blue. Red blood is oxygenated blood and blue blood is deoxygenated blood. \n\nHowever, all blood outside of the body is red because oxygenated blood is red and deoxygenated blood becomes oxygenated through diffusion instantly upon reaching the air.
1058331
Different blood types are formed with evolution:\n\nEvolutionary biologists theorize that the IA allele evolved earliest, followed by O (by the deletion of a single nucleotide, shifting the reading frame) and then IB. This chronology accounts for the percentage of people worldwide with each blood type. It is consistent with the accepted patterns of early population movements and varying prevalent blood types in different parts of the world: for instance, B is very common in populations of Asian descent, but rare in ones of Western European descent.)\n\nAs for other mammals:\n\nThe ABO system is the most important blood type system in humans. The associated anti-A antibodies and anti-B antibodies are usually powerful IgM antibodies. ABO IgM antibodies are produced in the first years of life by sensitization to environmental substances. ABO blood types are also present in other apes such as chimpanzees, bonobos and gorillas.
388847
blood is required in the liquid phase and required immediately. some rare blood types are frozen but the recovery from the frozen state is quite poor and takes sometime. most of the blood collected is used, but there is always a need for more.
863871
it is very simple \nif ur blood type is o+ than u can receive blood from o+ and o-\nif ur blood type is o- than u can only receive blood from O-
146212
O Negative is the universal donor.\n\nIndividuals with type O blood have red blood cells with neither antigen, but produce antibodies against both types of antigens. Therefore, a person with type O-negative blood can safely donate to a person with any ABO blood type and is called a "universal donor". However, an O-negative person can only receive blood from another O-negative person.
1156994
In the ABO blood type system, each person has 2 blood type alleles, one from each parent. The alleles can be A, B, or O. Which 2 alleles you have determines which blood type you will be: AA or AO is blood type A; BB or BO is blood type B; OO is blood type O; AB is blood type AB.\n\nThe +/- system is called the Rhesus factor and works in a similar way. There are 2 alleles: Rh+ (+ for short) or Rh- (- for short). A person with 2 copies of Rh+ (++) or only 1 copy (+-) will be +. A person with no Rh+ (--) will be -. \n\nTo answer your final question, a person who is O+ must have the alleles OO++ or OO+-. A person who is A+ can be AA++, AO++, AA+-, or AO+-. They can certainly share the same mother and father. One example is that the mother can be AO++ and the father is AO+-.
13809
Blood types are not evenly distributed throughout the human population. O+ is the most common, AB- is the rarest. There are also variations in blood-type distribution within human subpopulations. The figures given here are for people of European descent.\n\nType Frequency \nO+ 38% \nA+ 34% \nB+ 9% \nO- 7% \nA- 6% \nAB+ 3% \nB- 2% \nAB- 1%
102601
Yes, type O can recieve type AB. I am a type O.:O) Any other blood types, more than likely your body will reject it. Along time ago my cousin had a tropical disease called dengue fever(mosquito disease) in tropical countries and she was a type O and the blood bank had little type O blood, so they mixed A and B blood together and it worked. She is now a happy and healthy woman. :O)
324496
No there is no link.  Every non-scientific person seems to think that blood type is a major genetic factor that differentiates people.  The truth is, your blood type is just one of tens of thousands on minor genetic details that make you different from the person next to you.  I'm not saying blood type isn't important, it is very important when it comes down to blood transfusions, and to a lesser degree for organ donation.  This is important because an immune system tends to react with the "unknown" blood cells when used in a blood transfusion.  These cells may have minor changes to the sugar molecules attached to proteins in the red blood cell.  This makes them "foreign" and can cause severe blood clotting and death.\n   There are whole other sets of genes that will determine which types of foods you shouldn't each (allergic reactions) and need to each extra of (vitamin or other dietary deficiencies), but these are completely unrelated to your blood type.
1026160
Good info in the other answers but short and sweet  If you and your sibs are O  and 1 parent is O then the other parent must be AO genetically  type A blood. There is no way the 2nd parent could be AB
8023
Most blood transfusions are of packed red cells and not serum/platelets or white cells.  Red cells have no nuclei/genetic material.  Blood type and rH factor are important and mismatch can yield a type of rejection.  The white cells are ultimately "rejected"   In someone with an inactive immune system (chemo patient) the blood can attack the recepient!
956109
In humans and other hemoglobin-using creatures, oxygenated blood is bright red. This is due to oxygenated iron in the red blood cells. Deoxygenated blood is a darker shade of red, which can be seen during blood donation and when venous blood samples are taken. However, due to an optical effect caused by the way in which light penetrates through the skin, veins typically appear blue in color. This has led to a common misconception that venous blood is blue before it is exposed to air. Another reason for this misconception is that medical charts always show venous blood as blue in order to distinguish it from arterial blood which is depicted as red on the same chart.
795936
in order for a child to have O blood, both parents must have one O allele (because O is recessive so the child needs 2 O alleles). Since we know that the father definitely has one A and the mother has one B, the parents' genotypes are\nmale: AO\nfemale: BO\n\n\nAO x BO\n\n-------A------O\n---B--AB----BO\n---O--AO---OO\n\nI hope you could understand my punnett square; using dashes for spacing is ugly! Their children will have 25% chance of AB blood, 25% A (genotype AO), 25% B (genotype BO), and 25% O.
222531
Why Do People Have Different Blood Types?\nFor Your Information \nThe types of proteins, glycoproteins and glycolipids found (or expressed) on the surface of red blood cells define blood types. In addition, blood types, or at least the genes responsible for them, are inherited. Karl Landsteiner described the original blood types - A, B, and O - in 1900 and doctors now recognize 23 blood group systems with hundreds of different types. Many of the blood type antigens (and the antibodies that react with them) have been discovered as a result of transfusion incompatibilities. Some of these molecules have additional functions that are at least as important as conferring compatibility (or lack of compatibility) on transfusion recipients however. The advent of sophisticated biochemisty and molecular biology has helped to characterize a number of these entities. Although it appears that the majority of the molecules are not essential for red cell function, some have specific functions on the red cell membrane such as allowing substances to enter and exit the red cell (transporters) or binding certain substances to the cell surface (receptors). \n\nFor some blood types, evolution and environmental selective pressures are clearly important for their persistence. For example, the Duffy blood type includes a receptor that allows certain types of malarial parasites to enter the red cell. Thus, in some malarial areas of Africa, populations with Duffy negative blood types have a distinct survival advantage because absence of the Duffy antigen provides a measure of protection against malaria. The percentage of people lacking the Duffy antigen is much higher in these locations than in areas not endemic for malaria. \n\nWe do not yet know the functions of the A and B blood group factors. (The O blood type is defined as the absence of A and B factors). They are most likely important, however, because they are expressed on many cells and tissues in addition to blood cells and circulate in the plasma as well. There are statistical differences in the frequency of certain malignancies that correlate with the ABO blood groups. Group A subjects have about a 20% greater risk of developing cancer of the stomack than do Group O subjects, for instance, whereas Group O subjects appear to have a greater risk of developing ulcers. The reasons are unclear. These disease susceptibilities are unlikely to confer a signficant survival advantage on a population, however, because (unlike malaria) they often occur beyond a subject's reproductive years. On the other hand, there is some evidence that Group O individuals are more susceptible than other blood type individuals to the agent that causes bubonic plague and Group A individuals are more susceptible to smallpox virus. These correlations may account for the increased frequency of the B gene in China, India and parts of Russia, which suffered epidemics of both of these diseases. Infectious organisms that carry A and B like antigens may have indeed played a role in the somewhat different distribution of blood types worldwide. \n\nFinally, a number of myths exist about blood types. Claims have been made that Group A people have the worst hangovers, Group O people the best teeth and Group A2 people the highest IQs, for example. With these and other purported associations, both the scientific basis and evolutionary significance are limited at best.
31990
No this combination is not possible. Blood type is a combo of one of each parent's alleles.  Therefore an O could produce an A with an AB or A mother or a B with an AB or B mother, but not an AB.  Please use the link to calculate.
1139472
Rh + is dominant, - is recessive; the A blood type can be either homozygous or heterozygous (its multiple allelles), so babies could be O+ or O-, A+ or A-.