Module 1: Gene Symbols

This page will deal with gene symbols.  Here's the plan for symbols:

Digital Assets for Open Genetics
Module 0:  Introductions
Module 1:  Gene symbols module
v Relevant chapter:  3
v Submodules:
Ø   1.1 The power of good labels
§  1.1.1 Video introduction The Power of Symbols




§  1.1.2 Exercise:  identifying pacemakers from
§  1.1.3 Challenge (ungraded): what kinds of things might we desire to communicate using a gene symbol?
§  Outcome:  The student will be able to describe features of a powerful nomenclature system.

Ø  1.2 Basic Nomenclature
§  1.2.1 Video description Nomenclature Systems
·      Text links
¨     Page 3-2 section 3.2.1 (Terminology)
¨     Figure 3.2 page 3-2 (Mendel’s phenotypes)
¨     Table 3.1 page 3-3 (Examples of symbols)
¨     Section 3.2.2 on page 3-3 describes dominant alleles as capitalized
·      Single letter
·      Subscripts
·      Superscripts
·      Slashes
§  1.2.2 Exercise:  which of the following are correct symbols for two alleles of the same gene? (choose all which are correct)
§  1.2.3 Video demonstration of loci (unlinked)
·      Text references
¨     Figure 3.3 page 3-3 (Biochemical basis of dominance)
¨     Figure 3.4 page 3-4 (Incomplete dominance; subscript symbols)
·      Correlate to mitosis and meiosis
·      Context:  only diploid cells need two letters
·      Biochemical function of a locus (gene)
·      haplosufficiency / haploinsufficiency
·      dominant / recessive
·      allelic series
§  1.2.4 Exercise:  identify linked genes from gene symbols
§  1.2.5 Exercise: drag  gene symbols into columns:  unlinked / linked / series AND rows:  dominant / recessive
§  Outcome:  The student will be able to recognize several standard nomenclature systems.
§  Outcome:  The student will correlate the terms “dominant” and “recessive” with biochemical action.
§  Outcome:  The student can create symbols that provide information consistent with inheritance features.

Ø  1.3 Linked Genes
§  1.3.1 Video demonstration linked genes
·      How to use a “slash”
·      How to use a semicolon
·      Distinguish “gene” from “allele”
·      Text references
¨     Table 3.1 on page 3-3 shows loci on homologues using a slash
§  1.3.2 Exercise:  identify ploidy of cell images
§  1.3.3 Exercise:  identify cell cartoons of various ploidy
§  Outcome:  the student will be able to describe chromosomal positioning of genetic loci using gene symbols.

Ø  1.4 Advanced Nomenclature
§  1.4.1 Video demonstration of “the rules”
·      Base state or reference state is the “wildtype” condition
·      Change from wildtype is a “mutant”.  This forms the basis of the symbol chosen.
·      If the mutant phenotype cannot be determined through not enough information, the symbol is based on the recessive phenotype.
·      In our system, choose three letters to form the symbol.  Always underline or italicize these.
·      If a mutant allele is dominant, capitalize the first letter.  If a mutant allele is recessive, use a lower case letter.  The subsequent two letters must be lower case.
·      The wildtype allele uses exactly the same symbology as the mutant allele (including capitalizations) but is delineated as a superscript “plus”.  That is the only difference between these symbols.
·      Text references
¨     Figure 3.9 page 3-7 shows w-/w+ system
¨     Section 3.2.2 on page 3-3 describes dominant alleles as capitalized
¨     Section 3.2.4 on page 3-4 shows an allelic series with “dominant” alleles as a capital; the recessive is lower-case.
§  1.4.2 Exercise:  given verbal descriptions, design a gene symbol using these rules
§  1.4.3 Exercise:  predict phenotypes from symbols given for diploid organisms.
§  Outcome:  the student can create symbols that maximize communication about genetic features using a defined system.
§  Outcome:  the student will be able to predict phenotypes from genotypes described using a defined system.

Ø  1.5 Sex Linked Genes
§  1.5.1 Video explanation using cartoon cells.
·      X-linked symbols
·      A new rule for a defined gene symbol system
·      Determining male
·      Determining female
·      Text references
¨     Section 3.5 (Sex-linkage:  an exception to Mendel’s Fisrt Law)
¨     Figure 3.4 page 3-4 (Incomplete dominance; subscript symbols)
§  1.5.2 Exercise:  given verbal descriptions, design a gene symbol using these rules
§  1.5.3 Exercise:  predict phenotypes from symbols given for diploid organisms.
§  Outcome:  The student will include features of a defined system to distinguish autosomes and sex chromosomes.

Ø  1.6 Summary:
§  1.6.1 Video wrapup
·      Definition of a locus
·      Linked and unlinked genes
·      Context regarding gene symbols
¨     name after mutant phenotype or recessive
¨     indicate linked genes
¨     indicate sex linkage



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