Genetics

–the study of heredity heredity? –passing of traits from parents to offspring Traits –Distinguishing characteristics that are inherited, ie eye color, leaf shape, tail length Genetics

Father of genetics Gregor Mendel born in Austria, 1822 monk, lived in monastery worked with pea plant work published in 1900’s,after his death Genetics

Father of genetics Why was the pea plant so good? –grow easily –available –self pollinating –display traits easy to see –produce a large number of offspring Genetics

Father of genetics 7 main traits Genetics

Generations Mendel would cross pollinate the pea plants with different traits and observe the offspring produced. cross between parents with different traits is called a hybrid P = parental generation F means filial –F 1 generation = offspring from the parent –F 2 generation = offspring from offspring from parents. Genetics

Generations Genetics

Mendel’s Laws Cross between smooth x wrinkled seeds –F1 = all smooth Genetics

Mendel’s Laws Mendel concluded that alleles segregate from each other during the formation of gametes Law of Segregation –Organisms inherit two copies of each gene, one from each parent. –Organisms donate only one copy of each gene in their gametes, thus 2 copies of each gene segregate, or separate, during gamete formation. Genetics

Mendel’s Laws Law of Segregation –Ex GG plant will send an G allele while a gg plane will send a g allele –What alleles can a Gg plant give? –G or g Genetics

The same gene can have many versions! Allele- any of the alternative forms of a gene that may occur at a specific locus. They may be HOMOZYGOUS-two of the same alleles at a specific (could both be white flowers) Or they may be HETEROZYGOUS-two different alleles at a specific locus. (one for white, one for purple!)

Genes influence the development of traits Genome-ALL of an organism’s genetic material Genotype-refers to the genetic makeup of a specific set of genes Phenotype-physical characteristics, or traits, of an individual –Hidden genes don’t matter in the phenotype

Mendel’s Laws Law of Dominance –some alleles are dominate (CAPITAL letter) and some are recessive (lower case letter) –ex the allele for tall (T) pea plants is dominant to the allele for short (t) pea plants - An allele is dominant simply b/c it in a heterozygote it is expressed and the other allel is not. Genetics

Punnett square –A grid system for predicting all possible genotypes resulting from a cross. The axes represent the possible gamete genotypes of each parent Grid boxes show possible genotype of offspring from those two parents. –find genotypes of parents –purple Pp segregate alleles – P p; P p Genetics

Punnett square Looking at results How many of each genotype are possible –1 PP, 2 Pp, 1pp know the phenotype of each genotype Genetics

Punnett square Looking at results How many of each genotype did you made –1 PP, 2 Pp, 1pp know the phenotype of each genotype 1PP homozygous dominant 2Pp heterozygous 1pp homozygous recessive Genetics

Punnett square Looking at results know the genotype ratio –1 PP: 2 Pp: 1pp –1:2:1 –A hybrid cross will always give you a 1:2:1 ratio Genetics

Punnett square Looking at results know the phenotype ratio –3 purple:1 white – 3:1 Genetics

Mendel’s Laws Cross between smooth x wrinkled seeds –F1 = all smooth –F1 x F1 –F2 = 3 smooth, 1 wrinkled Monohybrid cross –Examine the inheritance of only 1 specific trait. Genetics

Mendel’s Laws Cross between smooth x wrinkled seeds –F1 = all smooth –F1 x F1 –F2 = 3 smooth, 1 wrinkled Where did the recessive trait in the F2 come from? –some how they were carried but not expressed in the plant Genetics

Mendel’s Laws Looking at two different traits at the same time, Mendel found they were not always paired together. –ex yellow & round do not always show up together in offspring Dihybrid crosses-examine the inheritance of two different traits Genetics

Mendel’s Laws Law of Independent Assortment –alleles for different traits segregate independently of one another ex yellow seed color is independent of smooth seed texture –getting one trait does not guarantee you another trait Genetics

Mendel’s Laws Law of Independent Assortment –made possible because of? –Meiosis Genetics

NON-MENDELIAN GENETICS

Patterns of Inheritance incomplete dominance neither allele is dominant to the other both are expressed equally, often a blending of the two traits occurs Genetics

Patterns of Inheritance incomplete dominance C R is not dominant to C W Genetics

Patterns of Inheritance codominance two or more alleles are expressed at the same time both are expressed in patches on the organism Genetics

Patterns of Inheritance codominance C S and C D are both expressed in patches Genetics

Patterns of Inheritance codominance human blood types –blood types code for protein on surface of red blood cells –A, B, O, AB Genetics

Patterns of Inheritance codominance human blood types Genetics

Patterns of Inheritance codominance human blood types Genetics

Patterns of Inheritance codominance human blood types –cross a father with AB blood with mother O blood Genetics

Patterns of Inheritance human blood types also demonstrate multiple alleles multiple alleles refer to a trait (one gene) which is coded for by more than two alleles –What alleles are present in human blood? –I A, I B, i Genetics

Patterns of Inheritance Determining sex of offspring punnett square can help predict the sex of offspring female is –XX male –XY Genetics

Patterns of Inheritance sex-linked traits –traits found on sex chromosomes, X or Y chromosome (all non-sex chromosomes are autosomes) X chromosome is larger = more traits female is XX, male XY –traits on the X chromosome are more likely to be expressed in males –ex hemophilia, colorblindness Genetics

Patterns of Inheritance sex-linked traits sex-linked dominant Genetics

Patterns of Inheritance sex-linked traits sex-linked recessive Genetics

Tracking inheritance pedigree –traits can be tracked over several generations –affected individuals Genetics

Tracking inheritance karyotyping –tool used to look at chromosomes of individuals to look for mutations Genetics

Tracking inheritance nondisjunction failure of chromosomes to separate during cell division Genetics

Tracking inheritance nondisjunction Genetics

Frontiers of Biotechnology!

I. DNA manipulation A.During recent years, scientists have developed a technique to manipulate DNA, enabling them to study DNA and genes. B.A DNA molecule is too small for a scientist to cut themselves, so it is cut by special restriction enzymes.

II. Restriction Enzymes A. Used by bacteria to cut up DNA of viruses. B. Many different types that cut DNA at different sequences.

III. Copying DNA A. Often, DNA samples are very small. B. In order to get enough DNA to study,a polymerase chain reaction (PCR) is used to copy the same segment over and over.

IV. Separating DNA A. Gel electrophoresis separates the cut DNA by length, using an electrical current.

V. How is the DNA used? A.Genetic engineering- new genes can be added to an organisms DNA. B.Mutations and genetic diseases can be shown through different DNA fragments. C.A DNA fingerprint can identify a criminal, body, or missing person. D.DNA from different species can be compared to determine their relationship.

I. Genetic Engineering A.When humans make a change in an organism’s DNA code. B.In recombinant DNA, genes from one species can be inserted into another. C.Is frequently used in many of the foods we eat.

II. GM foods A.These are crops that have been genetically engineered (modified).They are also called transgenic, because they have genes from another species. B.GM crops make up 52% of the soybeans and 25% of the corn we eat.

III. How is it done? A.In bacteria: 1.A restriction enzyme is used to cut a gene. 2. The gene is added to a bacterial plasmid using sticky ends. 3. The plasmid is added to a bacteria, which makes many copies of the plasmid.

B. In plants: 1. The bacteria is modified (see A) 2. The modified bacteria can be allowed to infect a plant

C. In animals: 1. A fertilized egg cell must be used. 2. The foreign DNA is inserted into the nucleus using restriction enzymes and sticky ends. 3. The egg is implanted in a female. 4. The female gives birth to the transgenic organism.