Making a Pedigree Chart A family history of a genetic condition

Quick Review Genotype = what genes someone has Genes are usually represented by a letter, a capital letter for the dominant trait, a small case for the recessive. Example: Tongue Rolling is dominant, so we use R to represent the tongue rolling Inablility to roll your tongue is recessive so we use r to represent the non-rolling gene For every trait, you get a gene from each parent

Genotypes and Phenotypes Mom and Dad are Rr-that is their genotype, they can also be described as heterozygous-they have 1 of each gene What is their PHENOTYPE? The youngest son has a genotype of rr-he is Homozygous recessive-2 copies of the recessive gene His phenotype? tongue rollers Rr Rr I can’t Roll my Tongue! non-roller Rr rr Rr Rr

Some common dominant and recessive traits Widow’s peak is dominant. You can be homozygous dominant (WW) or heterozygous (Ww) and you will have widow’s peak What is your genotype and phenotype if you’re homozygous recessive? ww, no widow's peak

Making a Pedigree Chart Pedigree charts are made to chart family history and see how traits are passed A genetic counsellor will use pedigree charts to help determine the distribution of a disease in an affected family

Symbols Shade individuals that have the trait you’re studying Boys = squares (Lucy always calls Charlie Brown a ‘block head’) Girls = circles

Married-connected at side Siblings-connected at TOP not at the side (hopefully not siblings AND married) Oldest child-to the left Question-if shaded individuals in this pedigree have blue eyes, what is the GENOTYPE of the parents? both must be Bb

Other Divorced, separated Deceased Identical twins Fraternal twins

Organizing the pedigree chart Generations are identified by Roman numerals I II III IV

Organizing the pedigree chart Individuals in each generation are identified by Arabic numerals numbered from the left Therefore the affected individuals are II3, IV2 and IV3 I II III IV 3 4 5 6 7 2 1

What’s going on? Shaded = blue eyes 1 and 2 split after having 4, 2 then had kids with 3 and split with her too after 5-9 were born Genotypes of 1, 4,7? Genotypes of 2 & 3? Genotypes of 5,6, 8, 9, 10, 11, 12? 1 2 3 bb 6 10 4 5 7 8 9 Bb 12 could be BB or Bb 11 In what generation are there twins? III

Time to practice… Complete the practice worksheet on pedigrees in class (we will review) Pedigree swap activity Homework assignment – YOUR CHOICE!

Make your own pedigree Using your own family, make your own pedigree chart Must at LEAST include grandparents, parents, & your generation Pick one easy dominant or recessive trait and shade individuals that have it. You can guess who has it if you don’t know for sure. (Don’t pick a trait that EVERYONE in your family has) Label yourself, grandparents, cousins, etc Put a key on the pedigree so I know what shaded means. Ex.- shaded people have widow’s peak OR…you may create a pedigree chart for a fictional family of your choice. For example, a family in a book you read or a movie you have seen (ex: Twilight series, Harry Potter, etc)

Which technology was important to the development of the cell theory?

Microscope

The monk who worked with pea plants to discover the patterns of heredity was

Gregor Mendel

The person responsible for taking the x-rays which led to the discovery of the structure of DNA was

Francis Crick

Chemical which contains the information for an organism’s growth and functions is the

DNA

The unit of heredity that determines a particular trait is known as a

Phenotype

The smallest unit that can perform the basic activities of life is the

Cell

Four molecules that write the DNA code are

Nucleotides

Different forms of the same gene are called

Alleles

Traits that are coded for on DNA are considered _________; while those that are obtained by means other than genetically are considered  

Inherited; acquired

The step that follows mitosis during which the cytoplasm divides is called

Cytokinesis

What is the proper order for the steps of mitosis?

DNA replicates during Which phase?

An example of a codominant human trait is

a)Freckles b)Earlobes c)Hair color d)Blood type

An example of a recessive trait in humans is

a)Freckles b)Unattached earlobe c)Straight hair d)Brown eyes

A human female would have which set of sex chromosomes?

a)XX b)XY c)YY d)XxYy

Cells that contain half the usual number of chromosomes are

Gametes

Crossing organisms to produce offspring with desirable trait is called

Selective breeding

Any change in DNA is called

Mutation

Radiation treatments can be dangerous because they can

Kill healthy cells

Table which represents the possible combination of parental alleles

Punnett square