Blood Bank chapter 4

State three factors that differentiate blood group systems

• Structure and location of antigens

• Antibodies that are elicited

• Genetic control of antigen expression

Differentiate between genotype and phenotype

• Phenotype: Physical expression of inherited traits

• Genotype: Actual genes inherited from each parent

Identify the purpose of pedigree charts and punnet squares

• Pedigree: Diagram that illustrates the inheritance patterns of the family study

• Punnet squares- Used to calculate the frequencies of different genotypes and phenotypes of offspring

Compare and contrast the patterns of inheritance

• Sex-linked dominant- Will be expressed if passed from father to daughter

• Sex-linked recessive- Males inherit trait from carrier mothers

Discuss Mendelian principles

• Independent segregation: Law that refers to transmission of a trait in a predictable fashion from one generation to the next, in which one gene from each parent is passed to the offspring

Explain the manifestation of silent genes in blood bank

• Genes that do not produce a detectable antigen produce; also known as amorphs

• Null-Not there

Identify the purpose of calculating combined phenotypes

• Can illustrate probabilities of phenotypes from known or inferred genotypes

Display how to calculate the combined phenotypes in order to estimate the number of red cell units that should be screened for the corresponding antigen

• Convert the percentages to decimals and multiply together

Identify three methods of performing parentage testing

• Red cell antigens

• HLA

• Molecular methods

Identify the purpose of calculating combined phenotypes

• Can illustrate probabilities of phenotypes from known or inferred genotypes

How to calculate the probability of homozygous and heterozygous inheritance of alleles based on the Hardy Weinberg formula

• (p+q)²

• Has to equal 1 so whatever number is given subtract from one

Discuss the principle of parentage testing

• That alleles that a child possesses must either be inherited by the mother or the father. The alleged father is tested for any genotypic markers that the child did not inherit from the mother

List four uses for molecular testing techniques

• Tissue typing

• Paternity testing

• Recombinant technology for reagent and pharmaceutical manufacture

• Viral marker testing

Explain the procedure of hybridization

• Binding of two single-stranded DNA segments by base pair sequenced

• DNA fragments may be identified through the use of necleic acid probe. A nucleic acid probe is a short segment of DNA of a known sequence that is labeled with radioisopoe, fluochrome, enzyme, or chemiluminescent substrate. This probe is added to a sample of denatured DNA, and will bond to the corresponding DNA sequence if it exists in the sample

Discuss amplification

• Replicates DNA or RNA in samples, probes, or signals

• Used in cases in which amount of nucleic acid is low due to sample size or the target that is measured

Identify the test used for amplification of DNA

• PCR

Identify the purpose and source of Taq polymerase in polymerase chain reaction (PCR)

• Enzyme that synthesizes new strands of DNA; found in bacteria known as thermus aquaticus which is found in hot geothermal water and can sustain

Discuss the purpose of primers in PCR

• Short pieces of single-stranded DNA that are complementary to opposite strands that flank the target DNA; Mark the sequence to be amplified and provide initiation site for Taq polymerase

Identify uses for PCR in blood bank

• Creates millions of copies of target DNA sequence from one theoretical copy of the sequence, within a few hours

• Consists of five components: target DNA, Taq DNA polymerase, Primers, Nucleotides, and a magnesium amplicon

Units of inheritance that encode certain traits or visible characteristics

• Genes

Diagram that illustrates the inheritance patterns of traits in a family study

• Pedigree chart

Used to calculate the frequencies of different genotypes and phenotypes of offspring

• Punnett square

Specific location where genes are located

• Genetic locus

Alternate form of a gene at a particular locus

Allele

Opposite

Antithetical

Having two or more alleles at a given locus

Polymorphic

Two different inherited alleles are equally expressed

• Codominant

Inheritance pattern in which the gene product is only expressed when inherited by both parents

• Recessive

Inheritance pattern in which the gene product is expressed over another gene

• Dominant

Gene that does not express a detectable product

• Amorphic

Law that refers to transmission of a trait in a predictable fashion from one generation to the next, in which one gene from each parent is passed to the offspring

• Independent segregation

Random behavior of genes on separate chromosomes during meiosis that results in a mixture of genetic material in the offspring; demonstrated by the fact that blood group antigens, which are inherited on different chromosomes, are separately and discretely expressed

• Independent assortment

Chromosomes other than sex chromosomes

Autosome

Same

• Homozygous

Different

• Heterozygous

Individuals who have heterozygous inheritance can display weaker reactions with reagents than these who have homozygous inheritance

• Dosage

Two or more genes that are on the same chromosome of a homologous pair

• Cis genes

Genes inherited on opposite chromosomes of a homologous pair

• Trans genes

Term that refers to the inheritance of two genes together because they are close to each other on a chromosome

• Linked genes

Linked set of genes

• Haplotype

Exchange of genetic material during meiosis after chromosome pairs have replicated; genes are exchanged but not lost

• Crossing over

Genes that do not produce a detectable antigen product

• Silent genes

Used to calculate a determination of the gene frequencies that produced a trait; Predicts probability of heterozygous and homozygous expression for each of the genes in a system

• Hardy-Weinberg Law

Testing is based on principle that the alleles a child possesses must either be inherited by the mother or father. The alleged father is tested for any genotypic markers that the child did not inherit from the mother

• Parentage testing

Binding of two single-stranded DNA segments by base pair sequences

• Hybridization

Replicates DNA or RNA in samples, probes, or signals

• Amplification

Required by Taq polymerase

• Amplicon

Double strands of DNA that carry genetic information. Humans have 23 pairs of chromosomes-22 pairs of autosomes and 1 pair of sex chromosomes

Chromosomes