Blood Banking Genetics Vocabulary

Flashcards of key vocabulary terms and definitions in blood banking genetics

Blood Group System

Groups of antigens on the RBC membrane that share related serologic properties and genetic patterns of inheritance.

Phenotype

Physical (observed) expression of traits.

Genotype

Actual genetic makeup.

Gene

Basic units of inheritance on a chromosome.

Locus

The site at which a gene is located on a chromosome.

Alleles

Alternative forms of a gene, are found at each locus

Antithetical

Antigens produced by opposite alleles

Polymorphic

Multiple alleles at a single locus

Recessive Genes

Gene is expressed only when inherited by both parents

Codominant Genes

Equal expression of two different alleles

Dominant Genes

Gene that is expressed over another gene

Amorphic Genes

Genes that do not express a detectable product

Independent Segregation

One gene from each parent is passed to the offspring

Independent Assortment

Blood group antigens from different chromosomes are expressed separately, resulting in a mixture of genetic material

Linkage

Occurs when 2 genes that are close to each other are inherited together

Haplotype

Each set of linked genes

Linkage Disequilibrium

Haplotypes tend to occur at a higher frequency than for unlinked genes

Crossing Over

Occurs when 2 genes on the same chromosome combine and produce 2 new chromosomes

Homozygous

A person who inherits identical alleles

Heterozygous

A person who inherits different alleles

Dosage

A variation in antigen expression due to the number of alleles present

Cis

Alleles on the same chromosome

Trans

Alleles on opposite chromosomes

Phenotype Calculation

Enables finding a unit of RBCs with certain antigen characteristics (i.e., antigen negative)

Hardy-Weinberg Formula

Calculates a determination of the gene frequencies that produced a trait

Polymerase Chain Reaction (PCR)

Rapidly and precisely multiplies specific DNA sequences

Sequence-Specific Primers (SSPs)

Primers are available in PCR trays to identifies antigen level

Sequence-Specific Oligonucleotides (SSOs)

A DNA probe allows the hybridized solution to be read and analyzed by a flow cytometer

Sequence-Based Typing (SBT)

Provides high-resolution, allele-level typing

Short Tandem Repeats (STRs)

Short sequences of DNA that are amplified to determine the percentage of engraftment in chimerism evaluation

Mitosis

Replication of genetic material in somatic cells

Meiosis

Replication of genetic material in gametes

Hemagglutination

Used to determine a patient's phenotype by observing the reaction of RBC antigens with antisera.

Xg Genes

Genes found on the X chromosome

Amplicons

Amplified DNA assessed using gel electrophoresis

Chimerism Evaluation

Uses differences in DNA sequence to determine the percentage of DNA from the donor in a stem cell recipient.

Red Blood Cell (RBC)

A component of blood that contains antigens on its membrane.

Human Leukocyte Antigens (HLAs)

Antigens identified by comparing and contrasting molecular techniques.

Hematopoietic Progenitor Cell (HPC)

Cell evaluated using short tandem repeat (STR) testing for chimerism.

Alloimmunization

Prevention of this by donor antigen screening.

DNA

Genetic material found in chromosomes within the nucleus of every cell.

Mendelian Principles

Principles applicable to blood group antigen inheritance, including independent segregation and independent assortment.

Gel Electrophoresis

A technique used to assess amplified DNA (amplicons) in PCR-based HLA typing.

BeadChip Technology

Technology using oligonucleotide primers attached to colored silica beads on a substrate.

Flow Cytometer

Instrument used to read and analyze hybridized solution in Sequence-Specific Oligonucleotides (SSOs).