Genetics

Heredity Heredity – characteristics inherited from parents to offspring through genes

Genetics The study of genes and heredity

Traits Characteristics that are inherited through genes

Gregor Mendel A monk in the 1800s First to identify heredity

Garden Peas Studied the traits in garden peas Tall/short Round/wrinkled Green/yellow pods Purple/white flowers

Background information Each trait or characteristic has 2 copies of DNA that code for that trait Each copy of the trait is called an allele Each organism has two copies of each allele

Conclusions Mendel had certain rules for heredity Characteristic, unit factor/gene/height Two contrasting traits/alleles/tall or short Another example pod color – green/yellow

The Rule of Dominance Alleles can be either dominant or recessive (strong or weak) Dominant alleles are observable Recessive alleles are not usually observable, when the dominant allele is present

The Law of Segregation Alleles for a gene separate when forming a sperm and egg

Law of Independent assortment Alleles for different genes are distributed to sperm and egg independently Could be tall and fat Short and thin Tall and thin Short and fat Why all siblings do not look exactly alike

Dominant The allele that is expressed – you can see it Use the first letter of the word and capitalize it C curly hair B brown hair

Recessive The allele that is not expressed It is covered up by the dominant allele It is there you just cannot see it Use the lower case for the recessive allele c for straight hair b blonde hair

Phenotype The way an organism physically looks Brown hair, tall

Genotype The copies of alleles or genes that an organism has Genetic make-up genotype controls the phenotype BB, Bb, bb

Homozygous – (Homo: same) Pure When an organism has 2 copies of the same allele BB – homozygous dominant bb – homozygous recessive

Heterozygous (Hetero: different) Hybrid When an organism has 2 different alleles for a gene one capital; one lower case Bb, Gg etc.

Parent or “P” Generation The 2 organisms that are used to reproduce

F1 Generation The offspring - babies

F2 generation The babies of the F1 or the grandchildren of the P generation

Incomplete dominance There is no dominant allele or recessive allele The 2 alleles are blended and make up a new physical appearance Ex. A red allele and a white allele can make a pink flower

Co dominance There is no dominant or recessive allele but both are expressed Ex: a chicken with white & black feathers Blood Types: A, B, AB, or O

Punnett Square A chart used to predict the probability of traits represented among offspring If 2 plants pollinate – predict what it would look like!

Monohybrid One cross because you are looking at only one trait

Pedigree A diagram representing a family tree The alleles that each person in the family has

Monohybrid Punnett Square Problems Height – tall is dominant to short Symbol for tall _______ Symbol for short _____ Phenotype – Homozygous tall male X short female Genotype Male _____ X Female ______

P1 Punnett Square F1 genotype ratio F1 phenotype ratio

Monohybrid Punnett Square Problems Height – tall is dominant to short Symbol for tall _______ Symbol for short _____ Phenotype – _______ male X _______ female Genotype Male _____ X Female ______

F1 Punnett Square F2 genotype ratio F2 phenotype ratio

Dihybrid Two crosses - you are looking at 2 traits

Dihybrid Cross Involves two characteristics (two pairs of contrasting traits) for each individual. Predicting the results of a dihybrid cross is more complicated than predicting the results of a monohybrid cross. All possible combinations of the four alleles from each parent must be considered.

Dihybrid Cross Example Purple (P) is dominate to white (p) Smooth texture (S) is dominant to wrinkled (s)

Human Blood Type There are three different alleles for human blood type. Each of us has two ABO blood type alleles, because we each inherit one blood type allele from our biological mother and one from our biological father. Blood Types Simplified IA A IB B i O

Each blood group is represented by a substance on the surface of red blood cells (RBCs). These substances are important because they contain specific sequences of amino acids and carbohydrates which are antigenic.

More Info… Allele from Parent 1 Allele from Parent 2 Geno-type Blood Type A AA B AB O AO BB BO OO Since there are three different alleles, there are a total of six different genotypes at the human ABO genetic locus.

Blood Types A & B Blood Types Possible Genotypes A AA AO B BB BO If someone has blood type A, they must have at least one copy of the A allele, but they could have two copies. Their genotype is either AA or AO. Similarly, someone who is blood type B could have a genotype of either BB or BO. Blood Types Possible Genotypes A AA AO B BB BO

Blood Type AB & O Blood Type Genotype AB O OO A blood test of either type AB or type O is more informative. Someone with blood type AB must have both the A and B alleles. The genotype must be AB. Someone with blood type O has neither the A nor the B allele. The genotype must be OO. Blood Type Genotype AB O OO

Rh Factor Rh Factor Possible Genotypes Rh+ Rh+/Rh+ Rh+/Rh- Rh- Rh-/Rh- There are 2 different alleles for the Rh factor known as Rh+ and Rh-. Someone who is "Rh positive" or "Rh+" has at least one Rh+ allele, but could have two. Their genotype could be either Rh+/Rh+ or Rh+/Rh-. Someone who Rh- has a genotype of Rh-/Rh-. Rh Factor Possible Genotypes Rh+ Rh+/Rh+ Rh+/Rh- Rh- Rh-/Rh-

Blood Transfusions When a blood transfusion is necessary, donor and patient blood must be compatible. If not, the patient’s body will react to the incompatible donor cells, leading to complications, maybe even death. U.S. percentage of the population shares your ABO grouping. O+ 37% O- 6% A+ 34% A- 6% B+ 10% B- 2% AB+ 4% AB- 1%