Patterns of Inheritance

Who was Gregor Mendel?
Gregor Mendel was the first "geneticist" to figure out a concrete law on inheritance. He was a monk in what was then Austria, working with the inheritance of pea plants. 

Are there diseases that are genetically transmittable?
Yes, many in fact. Thankfully most are recessive, due to evolution, ones that are dominant have mostly killed off their hosts.

What is incomplete dominance? 
A condition in genetics that causes both, blended or some traits of the parents to appear in the offspring.

The Facts: 
-The Law of Segregation is: A sperm or egg carriers only one allele for each inherited character because allele pairs separate from each other during the production of gametes
-The Law of Independent Assortment is: Each pair of alleles segregates independently of other pairs of alleles during gamete formation.
-The Rule of Multiplication is: 1/2*1/2 = 1/4, which is true for genetics when it comes to recessive traits
-The Rule of Addition is used to figure out the probability of certain phenotypes (Aa and AA produce the same phenotype)
-"Carriers" refers to those who carry a recessive gene for a disorder, but do not show signs of said disorder
-Cystic fibrosis is one of said diseases, which causes mucus to be produced in excess in many places in the body, including the lungs
-Chromosome Theory of Inheritance: Genes occupy specific loci on chromosomes and chromosomes that undergo segregation and independent assortment during meiosis.
-Recombination frequency is when the offspring have the phenotype of the parent.
-Sex-linked genes are ones that are specifically on the sex chromosomes, usually on the X
-Red-Green Color blindness is attached to the X, and is much more common in males, since they only have one. Females, having two, have the chance of having a non-affected X, which allows them full color vision.

Some Helpful Terms:
-Character: A heritable feature that varies among individuals
-Trait: A variant of a character
-Homozygous: Two of the same allele
-Heterozygous:  Two different alleles
-Phenotype: The physical traits
-Genotype: The genetic make-up
-Testcross: Mating between an individual of unknown genotype and homozygous recessive to figure out the genetic make up of the other
-Inbreeding: Mating of closely related organisms
-Codominant: Both alleles are expressed in a heterozygous individual
-Pleiotropy: Genes that affect more than one character

Diagram:

This is an example of a Punnett square, for the shape and color of peas. It is apparent that green and wrinkled are the recessive traits, while smooth and yellow are dominant. About 1/4 will be green, and 1/4 will be wrinkled- this being an example of the rule of addition. On that note, only 1/16 will be green AND wrinkled (rule of multiplication).








Summary:
This chapter discusses one of the coolest facets of biology- genetics and inheritance. GO GENETICS! But it starts off talking about Gregor Mendel, and how he came to study genetics. He was very meticulous in controlling which plants bred with which, giving some very concrete data. The punnett square was crucial in the field of genetics, giving us a good way of seeing how genetic variation operates.
Not only that, but it goes on to talk about the things that Mendel didn't know, such as incomplete dominance, co-dominance and sex linked genes.

A Cool Video:
http://www.youtube.com/watch?v=oVl8OH_7QSc