BIOL10005 Lecture Notes - Lecture 16: Abo Blood Group System, Dna Ligase, Red Blood Cell
Lecture 15 - Friday 26 August 2016
BIOL10005 - GENETICS & THE EVOLUTION OF LIFE
LECTURE 16
TECHNIQUES & MANIPULATION OF DNA
CHAPTER 9 -INHERITANCE
INHERITANCE OF A SINGLE GENE
BLOOD GROUPS, CODOMINANCE AND MULTIPLE ALLELES
•Although an individual can only carry a max of 2 alleles, more than 2 alleles of a gene can exist
in a population.
•The ABO blood group is an example of a gene that has multiple allelic forms in a population. 3
alleles, IA, IB and IO influence the ABO blood type of individuals.
•In some cases, the phenotype of both alleles is evident in a heterozygote. The phenotype here is
the tendency of RBCs from one person to clump (agglutinate) when exposed to blood serum from
another individual.
•Blood groups are due to two different carbohydrates on the surface of RBCs whose presence or
absence is determined by the ABO gene on chromosome 9.
•We do not produce antibodies against our own antigens.
•Group A people have A antigen on the plasma membranes of their RBCs and anti-B antibodies.
•Group B people have B antigen on their cells and anti-A antibodies.
•Group O people have neither A or B antigen on their cells and have both anti-A and anti-B
antibodies in their serum. Group O serum will clump all other red cell types, A, B and AB.
•AB people have both A and B antigens on their RBCs but their serum has neither anti-A or anti-
B antibodies. Cells from an Ab individual are clumped by serum from either A or B but do not
clump other RBC types themselves.
•Antibodies in serum bind to their target antigen on the foreign BCs, causing clumping. Thus a
group A person’s serum will clump a group B person’s cells and vice versa.
LINKAGE ON AUTOSOMES
EPISTASIS
•Epistasis is when the phenotype of one gene masks the phenotype of the other.
CHAPTER 14 - GENETIC ENGINEERING AND
BIOTECHNOLOGY
AN OVERVIEW OF RECOMBINANT DNA
•The essence of the initial recombinant DNA breakthrough was the ability to take small fragments
of DNA from the very large plant and animal genomes and introduce them into plasmids and
viral genomes to create recombinant DNA molecules.
CUTTING AND JOINING DNA
•A range of enzymes are used to create recombinant DNA molecules. DNA molecules are cleaved
with restriction endonucleases/restriction enzymes to produce segments of DNA (donor DNA).
•Different DNA fragments can be joined together using DNA ligase and DNA molecules can be
cloned into self replicating circular plasmids (vector DNA) forming a recombinant DNA molecule.
GENETIC TRANSFORMATION
•Transformation is when the vector-donor recombinant DNA construct is introduced into a
bacterial cell (host).
Document Summary
3 alleles, ia, ib and io influence the abo blood type of individuals: in some cases, the phenotype of both alleles is evident in a heterozygote. Group o serum will clump all other red cell types, a, b and ab: ab people have both a and b antigens on their rbcs but their serum has neither anti-a or anti- Cells from an ab individual are clumped by serum from either a or b but do not clump other rbc types themselves: antibodies in serum bind to their target antigen on the foreign bcs, causing clumping. Thus a group a person"s serum will clump a group b person"s cells and vice versa. Epistasis: epistasis is when the phenotype of one gene masks the phenotype of the other. Cutting and joining dna: a range of enzymes are used to create recombinant dna molecules. Genetic transformation: transformation is when the vector-donor recombinant dna construct is introduced into a bacterial cell (host).
