BIOL 2030 Lecture Notes - Lecture 4: Blood Type, Zygosity, Wild Type
4 – Extensions and Modifications of Basic Principles; Complementation
January 11th, 2016
Multiple Alleles:
• Wild-type gene: the allele mostly found in natural populations
• Allelic series: set of >2 alleles that occur within a given natural population
• Notations:
o Standard – AA, Aa, aa
o Allelic series – A1A1, A1A2…etc
o Drosophila example:
▪ Ebony = e
▪ Wild type = e+
▪ Mutant = e-
o Blood type example:
▪ O anti A/anti B (no antigens on red blood cells)
• ii
▪ A anti B
• IAIA or IAi
▪ B anti A
• IBIB or IBi
▪ AB no antibodies in serum
• IAIB
▪ *blood recipient reactions to donor blood
• Type AB is the universal recipient blood
• Type O is the universal donor
Paternity Determination
• Using blood types, one could determine if the child belongs to a father
• Ex. Mother – type A; father – type O; child – type B
o Child does not belong to the father
o Father must have blood type B
Modifications of Dominant Relationships
• To determine the relationship between allele pairs look at homozygotes, heterozygotes
and their phenotypes
o Complete Dominance
▪ The phenotype of the heterozygote is the same as the phenotype of one of
the homozygotes
▪ At phenotype level, AA=Aa NOT aa
▪ Molecular/Biochemical basis
• Typically, in a biochemical pathway, half the amount of “normal”
protein is produced by the heterozygote comparentd to the
dominant homozygote. If it is sufficient to express the phenotype
Haplosufficient
• Complete dominance and complete recessiveness are two extremes
of range of dominance relationships
find more resources at oneclass.com
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Document Summary
4 extensions and modifications of basic principles; complementation. Iaia or iai: b anti a. Ibib or ibi: ab no antibodies in serum. Iaib: *blood recipient reactions to donor blood, type ab is the universal recipient blood, type o is the universal donor. Paternity determination: using blood types, one could determine if the child belongs to a father, ex. Mother type a; father type o; child type b: child does not belong to the father, father must have blood type b. If it is sufficient to express the phenotype. Haplosufficient: complete dominance and complete recessiveness are two extremes of range of dominance relationships, incomplete (or partial) dominance, the phenotype of the heterozygote is intermediate between phenotypes of two homozygotes. The heterozygote phenotype may fall at any point within the range of homozygotes: at phenotype level, aa>aa>aa, ex. Bird plumage colour (black blue grey: codominance, the phenotype of the heterozygote simultaneously expresses the phenotype of both homozygotes.
