Marking Period 3: Gen Biology

Pedigrees

Tradition! We scarcely know the word anymore. We are afraid to be either proud of our ancestors or ashamed of them. We scorn nobility in name and in fact. We cling to a bourgeois mediocrity which would make it appear we are all Americans, made in the image and likeness of George Washington. Dorothy Day

We can look at the characteristics of  ancestors to predict characteristics of offspring.  The pedigree tool is a useful way to predict passing of characteristics in live stock and in people.  This is useful to geneticists in predicting the likelyhood of genetic disease being passed to one's children.

Dominance

Things aren't always what they seem.  You are only seeing part of me.  There is more than you could ever know behind the scenes. Francesca Battestelli

Mendel came up with the concept of dominant and reessive characteristics, but was limited by the pea chcracteristics hee was studying.  There is a little more to inheritance patterns that simple dominance.  This unit will explore some of the nuances of dominance as it pertains to oorganisms other than the pea Mendel relyed on.

 

Mendelian Genetics

The relationship between Genotype and Phenotype is rarely as simple as in the pea plant charateristics Mendel studied. Anon.

Gregor Mendel was able to determine the basic patterns of inheritance by observing how physical characteristics were passed from one generation of pea plant to another.  There were many limitations he had to overcome, not least of which was the mechanism for such inheritance.  He is considered the father of modern genetics for the ideas and models he proposed.

Punnett Squares

The 50-50-90 rule: anytime you have a 50-50 chance of getting something right, there's a 90% probability you'll get it wrong.  Andy Rooney

The characteristics of an individual are controlled by the combination of genes from two parents. It is important to recognize that not all combinations of genes are equally likely; in fact, we can predict the probability of any specific combiation using statistical methods.  Reginald C. Punnett developed a method to determine the statistical likelyhood of a particular outcome.  The elegance of this method is that we create a tabular summary of possible combinations of maternal allele's with paternal allele.  These tables can be used to examine the genotypic outcome probabilities of the offspring of a single trait (allele), or when crossing multiple traits.

Inheritance

Genetics explains why you look like your father, and if you don't, why you should  Anon.

It is important that we realize how far we have come in such a short time.  It wasn't so long ago that we didn't know anything about the invisible world around us - the world of cells and microbes.  The development of the microscope opened up a whole new world to biologists, and allowed us to discover so much about life.

Co-Dominance

Tradition! We scarcely know the word anymore. We are afraid to be either proud of our ancestors or ashamed of them. We scorn nobility in name and in fact. We cling to a bourgeois mediocrity which would make it appear we are all Americans, made in the image and likeness of George Washington. Dorothy Day

Some characteristics don't follow the siple Mendelain rules we've learned so far.  These characteristics blend together when the alleles are neither dominant nor recessive to one another.  We call this condition "Co-Dominance", and we will look at a couple of different situations where this occurrs.  We'll use Blood Type, Hair texture and flower color in our examples, because each of these demonstrate these conditions.

Sex-Linked Traits

Tradition! We scarcely know the word anymore. We are afraid to be either proud of our ancestors or ashamed of them. We scorn nobility in name and in fact. We cling to a bourgeois mediocrity which would make it appear we are all Americans, made in the image and likeness of George Washington. Dorothy Day

Some characteristics are attached to the sex of the individual  These characteristics are coded for on the 23 chromosome - the "X" and "Y" chromosomes (Sex Chromosomes).  These traits are always associated with the sex of an individual.  This section deals with some conditions associated with the sex chromosomes, including color blindness and hemophillia.

Introduction to Evolution

Evolution is a tinkerer. Francois Jacob

Evolution is the change of habitable traits to a population across generations.   We will explore this concept, and try to expain how it works.  This is a complicated topic that has a specialized vocabulary.  We'll have a lot of work to do here.

Evolution by Natural Selection

Natural Selection, as it has operated in Human history, favors not only the clever, but the murderous. Barbara Ehenreich

Evolution is the change of habitable traits to a population across generations.   We will explore this concept, and try to expain how it works.  This is a complicated topic that has a specialized vocabulary.  We'll have a lot of work to do here.