MUTATION AND VARIATION
CUT OBJECTIVE 26!!!
NON-MENDELIAN INHERITANCE
- Mendelian = Complete Dominance
- Only the dominant allele’s protein is produced
- When a yellow and purple parent produce a purple offspring
-
...
MUTATION AND VARIATION
CUT OBJECTIVE 26!!!
NON-MENDELIAN INHERITANCE
- Mendelian = Complete Dominance
- Only the dominant allele’s protein is produced
- When a yellow and purple parent produce a purple offspring
- Not all traits are simply determined by a single dominant and a single recessive allele.
- Incomplete Dominance (see Diana’s picture)
- A little of each allele’s protein is produced.
- Codominance
- A lot of each allele’s protein is produced.
- Polygenic - Multiple genes determine the trait
- Eye color
- Bell Peppers
- Colon Cancer - Human needs to have mutations in about 7 different genes.
- Sex-Linked Traits
- Gene for trait is on portion of “X” chromosomes not matched by “Y”
COMPLEXITY
- Variable Expression: All cells in an organism have the same genes, but only some are
used.
- Muscle Cell
- Pancreatic Cell
- Molecular “bookmarks” are put in each cell’s DNA to indicate which genes should be
active.
- Modifier Genes: Some genes can modify the effect of another gene.
- Albino: Gene stops production of pigment proteins
- Master Control Genes: Activate numerous genes to control complex tasks
- Environmental Effects: A cell’s surroundings can impact how genes function
- Diet and hormones
- Which is a bigger influence: Genetics or Environment? (Nature vs Nurture)
- Heterochromia: your eye has 2 distinct color
MUTATIONS
- Mutations produce new alleles (versions of genes)
- Mutation: DNA is altered
- “Big” Chromosomal Mutations - structured changes or irregular number
(uncommon)
- Base “Point” Mutation - common
- Mutations in sperm and eggs can be passed on to future generations.
- Causes of Mutations
- Mistakes during DNA replication
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