GENETICS

Nicotiana Prediction % Green _______ % Yellow _______

HYPOTHESIS A. The blue tailed critters received all the tail color genes from the blue tailed parent. B. The blue tailed critters got most of the tail color genes from the blue tailed parent, only a little bit of genes form the orange tailed parent. C. The blue tailed critters received half their genes from the blue tailed parent and half their genes from the orange tailed parent, but the blue tail genes overwhelmed the orange tail genes.

Targets A. Tell what determines an organisms traits. B. Define Gene and Allele, tell where they are found, and what they are made of. C. Distinguish Genotype and Phenotype; Homozygous and Heterozygous. D. Explain Mendel’s Laws.

Targets E. Describe Co-Dominance and Incomplete Dominance as types of inheritance. F. Complete a Punnett Square using dominant, recessive, co-dominant and incomplete dominant traits. G. Analyze genetic patterns of inherited traits in pedigrees.

I. Inheritance of Traits A. Genetics Lingo 1. Gene : a segment of DNA that carries a code for a trait. 2. Allele : the different forms a gene may have for a characteristic.

3. Heredity : the passing of traits from parents to offspring. 4. Genetics : the science of how traits are inherited.

B. What Determines Traits? 1. Traits are determined by Genes and the Environment. A trait may be determined by more than one gene. 2. Inherited Traits – passed on from parents through genes. 3. Learned Traits – actions learned through training or experience.

C. How Are Traits Inherited? 1. Genetic info found in DNA is transferred from cells of parents to cells of offspring

2. Organisms have two genes for each trait, one from each parent.

II. Mendelian Genetics A. Gregor Mendel ( ) “the Father of Genetics”  Discovered the basic laws of inheritance.

B. Mendel’s Laws 1. Law of Segregation  Gene pairs separate when sex cells form.  Sex cells contain only one form of a trait.

keynote animation keynote animation 2. Law of Independent AssortmentLaw of Independent Assortment  Sex cells contain a random mix of chromosomes, not a pre defined set.  Each chromosome from any one pair is free to combine with any chromosome from the remaining pairs. (gene shuffling)  Traits are not passed down together.  Reason for genetic diversity.

Chromosomes align differently during meiosis.

3. Law of Dominance  The variation of one trait hides the expression of another trait. (one overwhelms the other)  Dominant : allele that is expressed.  Recessive : allele that is hidden

C. More Lingo 1. Homozygous : alleles for a trait are the same. 2. Heterozygous : alleles for a trait are different. 3. Genotype : genetic makeup for a trait. (inward) 4. Phenotype : physical appearance of a trait. (outward)

 Ex: height in pea plants; T= tall, t= short TT = homozygous tall tt = homozygous short Tt = heterozygous tall Genotype (TT, tt, Tt) Phenotype >>>>>>

D. The Punnett Square 1. Predicts the possible combination of alleles in the offspring of two parents.  Probability calculator.

2. Monohybrid Cross

3. Testcross

III. Modern Genetics A. Incomplete Dominance (partial)  Offspring show an intermediate between those of its parents.

B. Co – Dominance (equal) 1. Two alleles are expressed at the same time.  Ex: blood types – 3 alleles A, B, O 2. A and B are co-dominant. Phenotype Genotype A AA – AO B BB – BO AB AB O OO

IV. Genetic Determination of Sex A. X and Y chromosomes Female: X X Male : X Y 1. Egg cells carry X only. 2. Sperm cells carry either an X or a Y.  If a Y chromosome is inherited >> male.  Probability – 1 : 1 ratio

Karyotype

B. X – Linked Traits 1. Traits controlled by genes that are located on the X chromosome.

2. Recessive X Linked Traits  Males: one recessive gene.  Females: two recessive genes.

Colorblind Test

V. Pedigrees A. Family Tree B. Importance : Inheritance data is collected within a family and used for genetic analysis.

Human Trait Variations EYE COLORHAIR COLOR BLUE GRAY GREEN HAZEL BROWN DARK LIGHT RED

Human Trait Variations EAR LOBESDOMINANT HAND

Human Trait Variations HAND CLASPINGVULCAN

Human Trait Variations FINGER CROSSINGHICHHIKERS THUMB

Human Trait Variations TONGUE ROLLINGPTC TASTING