Classical Genetics - Objectives Identify and label parts of chromosomes Describe Mendel’s discoveries Perform genetic crosses Identify and perform a karyotype Analyze probabilities Distinguish genotype and phenotype Use Punnett Squares Predict genetic outcomes Use a Pedigree Chart

A. The Chromosome Chromosome _______________ Thread-like strand made of DNA and proteins that transmits hereditary information. Chromosome Histones (proteins) DNA This is what we had to break down in the onion

There are _____ pairs of chromosomes in humans giving ______ Total chromosomes A. The Chromosome This picture shows two copies of the chromosomes. Both sides are a single _____________. chromosome ____________ Single Strands of a chromosome ____________ Center of two identical chromosomes ________ A specific place on chromosome that is a genetic trait (the color coded parts) Chromatids Centromere Gene

B. Karyotype ___________ An orderly arrangement of the chromosomes in an organism Karyotype Arrangement: Largest to Smallest First 22 pairs are called: Autosomes Last pair: ____________________ but may not match Sex Chromosomes XX = ________XY = ______ X is __________ than the Y chromosome FemaleMale Larger

B. Karyotype Karyotypes detect: __________________ Genetic diseases Find the mistakes? Partial deletion (2) Total deletion (16) Trisomy (21) ? 1.A _____copy of a gene 2.Trisomy 21 is ___________________ 3 rd Down’s Syndrome

__________ Type of organism with one copy of chromosomes. Some plants, algae, fungi. C. Inheritance Chromosomes are __________from parents inherited ___ from mother ___ from father 1 1 __________ Type of organism with two copies of chromosomes Haploid Diploid _________ Cells that contain one-half the genetic information; sperm and egg in humans Gamete

D. Genes and Dominance Let us say we are studying freckles. The blue gene is the gene for freckles. But the two genes are different! One gene codes for Freckles and is labeled ___. F The other codes for NO Freckles and is labeled ___. f F f _________ are different forms of the same gene. Alleles

D. Genes and Dominance F f ____________What the genes both are. Genotype ____________What the organism LOOKS like. Phenotype So the GENOTYPE IS ______ But what does the person LOOK LIKE? 1. Lots of freckles? 2. A few freckles? 3. No freckles? Ff

D. Genes and Dominance F f ___________ genes always override ____________ genes. DOMINANT RECESSIVE Dominant = ___________________ 1. Are not the most ___________ Like polydactylismpolydactylism 2. Most common are __________ Recessive = ___________________ 1. Act like they are ____________ CAPITAL LETTERS lowercase letters Turned off common wild type

D. Genes and Dominance F f GenotypePhenotype FF Ff ff FRECKLES NO FRECKLES Therefore our person has: This is called _____________________. Complete Dominance

C. Inheritance

E. Other Types of Dominance _________________________ The dominant and recessive blend together making a new phenotype. Incomplete Dominance RRrr Rr ________________ Both phenotypes are displayed. Neither is dominant Codominance

F. Punnett Squares E e E e Pupil size in guinea pigs E = ____________ e = ___________ Mother and father are both ___ Mother can give __ OR __ Father can give __ OR __ Ee E E e e Large pupil Small pupil ________________ shows all genetic possibilities of the offspring. Punnett Square

F. Punnett Squares EeEe EeEe EE Ee ee What % have genotype EE? ___________ What % have genotype Ee?___________ What % have genotype ee? ___________ What % have PHENOTYPE Small pupils?______________ What % have PHENOTYPE Large pupils?______________ ¼ or 25% ½ or 50% ¼ or 25% ¾ or 75% _________________________ Genotype EE; both dominant _________________________ Genotype ee; both recessive _________________________ Genotype Ee; mixed dom/rec Homozygous Dominant Homozygous Recessive Heterozygous

F. Punnett Squares In orchids, Purple flower (P) is dominant to White (p). If a Pp flower is crossed with a pp flower, show the Punnett square What percent are Purple? ____________ What percent are White? _____________

F. Punnett Squares - Dihybrid _____________________ using a Punnett square to track ONE genetic trait. Monohybrid crosses _____________________ using a Punnett square to track TWO genetic traits. Dihybrid crosses Test cross of peas Y = y = W = w = Yellow Green Wrinkled Smooth Parent peas’ genotypes: YyWw x YyWw

F. Punnett Squares - Dihybrid YyWw x YyWw

F. Punnett Squares - Dihybrid YW Yw yW yw YW Yw yW yw YYWW YYww YYWw YyWW yywwYyWw Yyww YyWw yyWW yyWw % Yellow/Wrinkled: _______ % Yellow/Smooth:________ % Green/Wrinkled: _______ % Green/Smooth:________

G. Gregor Mendel Gregor Mendel is called _____________________ 1. Was a _______ 2. Studied ____________ 3. Discovered the ______ laws of genetics The father of genetics Monk Pea Plants 2 Law 1: Law of Segregation: Alleles __________ during formation of gametes (sperm and egg cells) Law 2: Independent Assortment: Each Trait is ______________ of one another separate Independent

H. Pedigree Chart Male = Female = Sexual union = Offspring =

H. Pedigree Chart Recessive gene on X chromosome; affects males more than females.

H. Pedigree and X-linkage Males with trait are: X r Y Females with trait are: X r X r Males without the trait are X R Y

I. Meiosis ___________ Cells with two copies of chromosomes Diploid ___________ Cells with one copy of chromosomes Haploid What cells need to be haploid? GAMETES: The egg and sperm cells Gametes need to be haploid so you get 1 copy of chromosomes from each parent: 1 chromosome from mother 1 chromosome from father = 2 copies!

I. Meiosis Just like Mitosis!

I. Meiosis NO interphase, This means NO DNA REPLICATION 1 copy of each Chromosome!

I. Meiosis – Mr. Anderson 8:25

I. Meiosis ________________ Exchange of genetic material between identical chromosomes. Crossing Over McClintock & Creighton - discovery Increases genetic diversity

I. Meiosis ______________ - Genes on the same chromosome are usually Inherited together. Mendel’s Independent assortment does not apply during meiosis Gene Linkage _____________ - The closer together genes are, the more likely to be linked. A map of the chromosome can be developed. Gene Map