25) Polymorph systems and their use in breeding Flashcards
Polymorphism
Two or more phenotypes present in the same species/ occurrence of more than one form.
Levels of polymorph differences
- Phenotype
- Genotype
Phenotype differences
- Morphological
- Serological
- Biochemical
Genotype differences
- Detectable:
- DNA
- Mitochondrial DNA
Blood groups
- RBC antigens on the cell surface
- Glycoproteins differ depending on sequence of sugar
RBC antigens arise from…
Alleles from a single locus belonging to the same blood group
Igs against most RBC groups are produced only after…
Challenge of an appropriate protein
Exception: Cattle + cat:
- First blood transfusion may go well
- Second transfusion may lead to problems
Neonatal erythrolysis
- Feto-maternal haemorrhage of placenta leaks RBC from the fetus into mother’s blood
- The mother produces Ig against fetus RBC
- Found in colostrums when foal starts suckling and dies within a few days
Number of blood groups for:
- Pig
- Cattle
- Dog
- Horse
- Cat
- Pig: 15
- Cattle: 13
- Dog: 12
- Horse: 8
- Cat: 1
Codominant inheritance
Expression of both alleles
Use of animal blood groups
- ID of animals
- Parentage control
- Research
Polymorph systems: Proteins
Restriction fragment length polymorphism
- Absence/presence of a restriction enzyme
- Fragments cut by restriction enzymes differ in size
- Electrophoretic pattern differs
- Electrophoresis applied to blood proteins
Function of restriction enzymes
- Cleave DNA at individual site
- Amino acids
- Proteins
Application of electrophoresis applied to blood proteins
- Separation of DNA according to size
- Used for parentage testing
MHC
- Used for immune system/compatibility between tissues
- 3 classes: 1, 2 and 3
- Responsible for antigen-presentation and immune reaction
- Self/nonself
MHC-1
- B2 microglobulins
- Several genes
- Each gene codes for a polypeptide
- The polypeptides combine
MHC-2
- B-lymphocytes
- Macrophage histoglobulins
MHC-3
Compliments
Microsatellites
- Noncoding repeating units of 2-7 base pairs in genome
- Inactive
- Homo-/heterozygotes
- Repeated many times known for mutations → Diversity
- Mutation can lead to misreading/mismatch
Microsatelites: homozygotes
Alleles are the same length
Microsatelites: heterozygotes
- Alleles differ in length
- Can be resolved from one another
SNP
- Single nucleotide polymorphism (C&G; A&T)
- DNA sequence variation
- Missense/nonsense reading can happen
- Found by PCR
Describe the variation of SNPs
- Single nucleotide difference between members of a species
- Most SNPs have 2 alleles: C & T
- Variation in DNA sequence can affect diseases
