Post on 16-Dec-2015
Outline
I. Meiosis and Sexual Reproduction
II. The Principles of Inheritance
III.How DNA is a code for traits
IV. Applications of DNA Technology
I. Meiosis and Sexual Reproduction
A. Meiosis Forms gametes needed for sexual reproduction.
Reduces the number of chromosomes by half.
Genetic recombination occurs. Nondisjunction is an error that can occur during meiosis.
I. Meiosis and Sexual Reproduction
B. Sexual Reproduction Gametes combine during the process of fertilization.
Fertilization restores the diploid number of chromosomes within the zygote.
II. The Principles of Genetics A. Origin of Genetics
B. Mendel’s Laws
C. Predicting genotypes and phenotypes
D. Patterns of inheritance
i) The Units of Heredity Genes, like chromosomes, are present in pairs. Different versions of genes are called alleles;they can be normal (wild-type) or mutant.
Most mutant alleles are recessive. These alleles, like chromosomes, segregate during meiosis.
There are more genes than chromosomes, so each chromosome must have many genes.
Alleles of different genes can recombine during meiosis.
ii) Law of Segregation
The two members of a gene pair segregate from each other into the gametes; so half the gametes carry one member of the pair and the other half of the gametes carry the other member of the pair.
Meiosis accounts for segregation of alleles
Before meiosis I, eachchromosome replicates
After meiosis I, thehomologues segregate
After meiosis II, eachgamete has one allele
iii) Law of Independent Assortment
Different gene pairs assort independentlyin gamete formation if the gene pairs areon separate chromosomes
C. Predicting Genotypes and Phenotypes
i) Punnet Squares
ii) Pedigree Analysis
iii) Hardy-Weinberg Equilibrium
i) Punnett Squares Reginald Punnett - English geneticist
Worksheet - Reindeer Recessives Download and print worksheet. Fill out and bring to class
Pedigree Charts Autosomal dominant - both sexes affected
Autosomal recessive - both sexes affected but fewer in number
Sex-linked recessive - only males affected
ii) Pedigree Analysis
Worksheet: Cystic Fibrosis Pedigree Download and print worksheet Fill out and bring to class
iii) Hardy-Weinberg Analysis Godfrey Hardy - British mathematician
Wilhelm Weinberg - German physician
Genetic Variation within Populations
Here is oneLocus with3 alleles
No individualcan have morethan 2 alleles
The gene pool isthe sum of all thealleles found ina population
X1 = .20X2 = .50X3 = .30
These are allele frequencies