ABO Blood Groups and Rh Factor

Rh factor

(The + or - after your ABO blood type) refers to the D antigen only. -Rh+ -Rh- -original experiments were done with blood from rhesus monkeys (Macaca mulatta), hence the name "Rh factor."

Plasma

-91% water -also contains albumin, globulin, fibrinogen, fats, proteins, enzymes, amino acids, salt, and sugar

Blood type AB

-None -A & -B antigens -A, B, AB, O (AB+is the universal recipient)

Cline

-a gradient of morphological or physiological change in a group of related organisms usually along a line of environmental or geographic transition -can also refer to a plot or map of the changes in allele, genotype, or phenotype frequencies over a geographic area

Acquired immunity

-a.k.a. Adaptive immune system -antigens trigger production of antibodies -antibodies attack pathogens in various ways: block actions, render harmless, facilitate ingestion by WBCs

Blood type B

-anti-A -B antigen -B, O compatibility

Blood type O

-anti-A & anti-B -H antigen -O (O is the universal donor)

Blood type A

-anti-B -A antigen -A, O compatibility

Pathogens

-any infective agent -bacteria -viruses -fungi -parasites -etc.

Syphilis

-caused by the bacterium Treponema pallidum. Infection is through sexual contact and can be passed from an infected mother to her child. -before penicillin, syphilis was almost 1.7x more common in A, B, and AB individuals than O individuals -high frequency of Type O blood among Native Americans may be related to natural selection by syphilis

Cholera

-caused by the bacterium Vibrio cholera, which is typically ingested by drinking water contaminated with feces -where endemic, cholera patients are more likely to have Type O blood. -Individuals with Type O blood also have increased severity of the disease and increased risk of developing severe diarrhea. -Ganges Delta area (India and Bangladesh): low frequency of O, high frequency of B

Bubonic plague

-caused by the bacterium Yersinia pestis, which is carried by fleas. -Yersinia pestis has an antigen on its surface very similar to the H antigen and may not be recognized as a pathogen in Type O individuals. -Individuals with Type O may have been at a selective disadvantage and died at higher rates that individuals with other blood types. -Black Death (1347-1351): killed 75-200 million people, killed 30-60% of Europe's population

Smallpox

-caused by various virus -individuals with Type A and Type AB blood may be more susceptible due to lack of anti-A antibodies. However, this hypothesis is controversial -if true, major river systems in India and China would have faced selected pressures from both cholera (against Type O) and smallpox (against Type A and Type AB), which would have resulted in higher frequencies of Type B blood.

Platelets

-cell fragments involved in blood clotting

ABO blood group system

-controlled by gene on chromosome 9 -alleles: A & B- codominant, O-recessive -genotype and phenotype: AA: type A, AO: type A, AB: type AB, BB: type B, BO: type B, OO: type O

Blood

-erythrocytes -leukocyte -platelets -plasma

Erythroblastosis fetalis

-hemolytic disease of the newborn. -sever condition of Rh-induced incompatibility.

Rh system

-includes at least 45 antigens not he surface of RBCs: D, C/c, and E/e are most important.

Rise of civilization

-increased population size -increased contact among individuals and groups -increased sedentism -these factors facilitated rapid spread of pathogens

Immune system

-innate immunity -acquired immunity

Possible ABO gene function

-may be to provide polymorphism that could respond to fast-evolving pathogens. -varying frequencies of ABO alleles in populations across the world are probably the result of past and ongoing epidemics, genetic drift, and gene flow. -rise of civilization

Innate immunity

-non-specific (all invaders treated the same) -skin, mucus, phagocytes, etc. -prevents microorganisms from entering body and works to eliminate microorganisms that have entered the body

Rh-induced incompatibility

-occurs when fetus is Rh+ (Dd) and mother is Rh- (dd) -The fetal RBCs have the D antigen and the mother's does not. -anti-D are produced by the mother. -normally no issues during the first pregnancy with incompatibility, but in subsequent pregnancies, the anti-D antibodies can attack the fetus. -erythroblastosis fetalis

Cholera, syphilis, bubonic plague, small pox

-pathogens that cause cholera, syphilis, bubonic plague, and smallpox, have been found to have antigens on their outer surface that are similar in structure to the A, B, and H antigens on the surface of RBCs. -our defense system will not recognize and produce antibodies against disease-causing organisms that have antigens similar to our own antigens. -individuals are more or less susceptible to these infections based on blood type

Antibody

-proteins produced in reaction to foreign antigen entering the body -attack pathogens in various ways: block actions, render harmless, facilitate ingestion by WBCs

Antigen

-proteins, carbohydrates, etc. that are attached to a pathogen

Erythrocytes

-red blood cells -when mature, lack a nucleus

Heterozygote's disadvantage with Rh-induced incompatibility

-selection acting against heterozygote -d allele frequency is relatively high in some parts of the world. -Western Europe: f(D allele) 65%, f(d allele) 35% -reason for this discrepancy is unknown.

Leukocytes

-white blood cells

Polymorphism

A discrete trait that exists in a populaiton in at least two forms -the frequency of the rarest allele must be no less than 1%. -genetic polymorphism -first genetic polymorphism to be discovered was the ABO blood group system.

Rh-

Do not have the D antigen (dd genotype).

Rh+

Have the D antigen (DD and Dd genotypes.

Genetic polymorphism

Monogenic (single-gene) trait with at least two forms.