Please update your TOC. Then set up the new page for Cornel notes. EQ: How are traits passed from parent to offspring.

Genetics The study of how traits are inherited from parent to offspring.                                

Heredity The passing of genetic material from parents to offspring.

Gregor Mendel Austrian Monk who performed the first major experiments investigating heredity. Studied the inheritance of traits among pea plants. Known as the father of genetics

Genes and alleles Genes are segments of DNA found in chromosomes. One version of the same gene comes from each parent. Alleles are the different form of gene for the same trait. One from the mother and one from the father. You have 2 alleles for every trait you have.

Dominant Dominant alleles are represented by a capital letter                                          Dominant This trait covers up the other allele and is the one that the offspring shows If one chromosome in the pair contains a dominant allele the other recessive one is hidden. Dominant alleles are represented by a capital letter Dimples are dominant.

Recessive The recessive trait is the allele that is covered up by the dominant one. The only way to express a recessive trait is to have both alleles recessive. Recessive alleles are represented by a lower case letter

Genotype and phenotype The combination of alleles you inherited from your parents is your genotype Your observable traits make up your phenotype

Homozygous If both alleles are dominant or recessive then they are said to be homozygous for that trait. The prefix homo means same.

Heterozygous If both alleles for a trait are different then they are heterozygous. The prefix hetero means different.

Multiple Alleles Some traits are controlled my many genes acting together Skin tone, shades of eye color, fingerprints etc…

Incomplete Dominance Each allele in a heterozygous individual influences the phenotype. The result is a blend.

Codominance Both Alleles are expressed in an offspring Blood type alleles have codominance There are 3 alleles that play a role in determining blood type. A B O

Punnett Square A graphic used to predict the possible genotypes of offspring Top of the Punnett square show the genotype from one parent and the side shows the genotype of the other parent. Each compartment shows an allele combination in potential offspring.

Sex determination XX chromosomes girl XY chromosome boy You will get one allele from each parent

Sex linked gene disorder Some inherited disorders are linked to the sex gene. Usually they are linked on the X chromosome. In order to have the disorder you must have it on all of your X chromosomes. Colorblindness and hemophilia are two examples X Y XX XY Xh XhX XhY

Recessive genetic disorder A genetic mutation or disorder. You must have both recessive alleles to express the trait. cystic fibrosis  : a disease that causes the respiratory system to produce thick mucus that clogs the lungs sickle cell disease : a disease where red blood cells form a "sickle" shape, rather than the typical donut shape, get caught in blood vessels, and cut off oxygen to tissues Tay-Sachs disease : a disorder causing mental retardation, blindness, seizures, and death

Pedigree A tool used to trace a trait through a family.

Pedigree