GENETICS
Chapter 11
Genetics=
Heredity=
The Genetic Question???=
Role of parents=
Blending Concept of Inheritance=
Role of Chromosome=
(Walter Sutton, 1900)
Gregor Mendel, (1866, 1900)=
-each organism has two sets of factors (genes) that control genetics.
Review:
How many copies of each c’some do you have?
How many copies of each gene do you have?
–all organisms use DNA as the genetic material
–DNA of eukaryotic cells is always
organized into c’comes.
–C’somes occur in pairs
Mendel’s Work:
Characteristic (Trait)=
Versions=
True Breeding Individual=
Cross Breeding=
P generation=
F1 generation=
His Results:
Law of Segregation
-each indiv. has 2 factors for each trait
-the factors segregate (separate) during
formation of gametes (meiosis)
-each gamete contains only 1 factor from
each pair of factors.
-fertilization gives each new individual two
factors for each trait (one from each
parent).
Mendel’s Work in Modern Context:
-each trait is controlled by two alleles.
-allele=
-gene locus=
-alleles may be dominant=
-alleles may be recessive=
-Meiosis explains the Law of Segregation
-Rule of Letters=
-True Breeding = Homozygous=
-Heterozygous=
-gene expression=
-masked or carried gene=
-Genotype=
-Phenotype=
Punnett square=
-laws of probability
-Monohybrid Cross=
-Genotypic ratio=
-Phenotypic ratio=
Test Cross=
Two-Trait Inheritance:
-Dihybrid Cross=
-Examines two characteristics at the same
time that can be inherited together.
Results:
Law of Independent Assortment
-each pair of factors segregates (assorts)
independently of the other pairs.
-all possible combinations of factors can
occur in the gametes.
Patterns of Inheritance:
1. Simple Dom./Rec.=
2. Incomplete Dominance=neither allele
is completely dom. over the other.
The result is an intermediate phenotype=
3. Co-dominance=
The result is a combination pheno.=
4. Polygenic Inheritance=
5. Environmental Effects=
6. Sex-linkage=
7. Epistasis=
8. Multiple Alleles=
Human Blood Types