Presentation on theme: "the study of inheritance"— Presentation transcript:
1the study of inheritance Geneticsthe study of inheritance
2There are 2 types of cell division: Mitosis- growth and repair involved in cells replicating themselves and all of their DNA into exact copies of original cellsMeiosis- sexual reproduction combining sperm & egg to produce an new and original organism that has half of it’s DNA from each parent into a original and unique combination of traits
3discovered heredity principles studied pea plants Gregor MendelFather of GeneticsAustrian monkdiscovered heredity principlesstudied pea plants
4What Is Heredity? Crossing Pea Plants Mendel devised a way to cross-pollinate pea plants.
5Common traits Mendel identified in Pea Plants: seed shape- round vs. wrinkledseed color-yellow vs. greenpod shape-pinched vs. smoothpod color-green vs. yellowflower color-purple vs. whiteflower position-top of stem vs. side of stemstem height- tall vs. short
6What Is Heredity? Alleles in Pea Plants Mendel studied the inheritance of seven different traits in pea plants.
7What Is Heredity? Results of a Cross In Mendel’s crosses, some forms of a trait were hidden in one generation but reappeared in the next. What was surprising about the offspring in the F2 generation?
8Vocabulary/Term List asexual reproduction sexual reproduction heredity traitgeneticspurebredparental P1 generationFirst filial F1 generationSecond filial F2 generationoffspringgenealleledominantrecessivehybridprobabilityPunnett squarephenotypegenotypehomozygousheterozygousVocabulary/Term List
9Sample CrossesIf a purebred tall pea plant with was cross pollinated with a purebred short pea plant describe it's offspring:Parent (P) Generation-First Filial (F1) Generation-Second Filial (F2) Generation-
10Sample Crosses Part 2If a purebred pea plant with purple flowers was cross pollinated with a purebred pea plant with white flowers describe it's offspring in each:Parent (P) Generation-First Filial (F1) Generation-Second Filial (F2) Generation-
11Sample Crosses Part 3If a purebred pea plant with wrinkled seeds was cross pollinated with a purebred pea plant with round seeds describe it's offspring in each:Parent (P) Generation-First Filial (F1) Generation-Second Filial (F2) Generation-
16Punnett Square-draw, label & complete A homozygous pea plant with yellow seeds is crossed with a homozygous pea plant with green seeds.y yYYDescribe the results in: percentages, ratios and fractions & use the terms heterozygous and homozygous in your resultsPhenotypes of each plant:Genotype of each plant
17Punnett Square- Draw, label & complete A heterozygous pea plant is crossed with another heterozygous pea plant with both with yellow seeds.Y yYyDescribe the results in: percentages, ratios and fractions & use the terms heterozygous and homozygous in your resultsPhenotypes of each plant:Genotype of each plant
18Punnett Square Practice: For each sample question fill in the Punnett square and describe the offspring in the F1 generation. Include:· Genotypes (Percentages, ratios, fractions of alleles)· Phenotypes (Percentages, ratios, fractions of each physical appearance)Sample #1: In Guinea pigs black fur color is dominant over white fur color. Suppose a homozygous black male guinea pig mated with a heterozygous black female guinea pig.(P) Parent Alleles:F1 Generation:Sample #2: In Guinea pigs Smooth fur is dominant over Cow licked fur. Suppose a heterozygous smooth male guinea pig mated with a homozygous cow licked female guinea pig.Sample #3: In Guinea pigs Solid fur color is dominant over Calico fur color. Suppose a homozygous Solid male guinea pig mated with a Calico female guinea pig.
19Dihybrid crossesSample #4: In Guinea pigs Black fur color is dominant over White fur color & Solid fur color is dominant over Calico fur color. Suppose a homozygous Solid black male guinea pig mated with a heterozygous Calico black female guinea pig. What would the offspring be like?(P) Parent Alleles:F1 Generation:Sample #5: In Guinea pigs Smooth fur is dominant over Cow licked fur and Black fur color is dominant over white fur color. Suppose a heterozygous Black & Smooth haired Male mated with a White & Cow licked haired female guinea pig. What would the offspring be like?Sample #6: In Guinea pigs Black fur color is dominant over White fur color & Solid fur color is dominant over Calico fur color. Suppose a heterozygous Solid black male guinea pig mated with a homozygous Calico black female guinea pig. What would the offspring be like?
21Vocabulary/Terms List Part 2: Mendel’s experiments with pea plants led to an understanding of how traits are controlled by genes. However, some traits are not controlled by genes with only 2 possible alleles.There are 4 other complex patterns of inheritance: Give an explanation of each below: Include examples!!!Incomplete dominance-Codominance-Multiple alleles-Polygenic inheritance-Define: Meiosis-What does the chromosome theory of inheritance state?Compare and Contrast the processes of Mitosis and Meiosis: be sure to include when/what each is used for and in what types of cellshttps://www.youtube.com/watch?v=zGVBAHAsjJM
22Patterns of Inheritance BlingwingsAn imaginary insect called the blingwing has three alleles for wing color: R (red), B (blue), and Y (yellow).What are the 6 possible allele pairs that can be inherited?2. Suppose the 3 alleles are codominant, what wing color would each pair of alleles produce?
23Nature: DNA, Genes and Chromosomes Genes make you who you are.This is a great opportunity to introduce or review DNA, genes and chromosomes. I have been able to introduce these three words and concepts to 5th graders as well as discuss and clear misconceptions with high school students. I use my chromosome model to cater to the students who need to see it all come together!DNA is found in the nucleus of a cell. If we look closer, unless the DNA is undergoing replication, it will be found in its chromosomal form (grab chromosome model). Chromosomes are typically drawn like X’s because we inherit two copies of each one of our chromosomes (show two copies with the model). When we study/talk about genes, we need to first unwind the DNA molecule to locate those genes (begin by separating the homologous chromosomes from your model and unwinding the yarn from a single chromosome). Once we have located those genes, we can then study the genes and the nucleotide bases that make up that specific region of DNA.Ask a student to help you by grabbing one end of he yarn from the model as you unwind the chromosome across the room. As the yarn unwinds, the colors will also separate into segments. Make sure you point out that each segment is a gene and that while a combination of genes is responsible for most of our traits, sometimes it takes a change in a single gene to completely change a physical trait!For Elementary or MS students:If your students are just learning about DNA, genes and chromosomes, I like to have them think of DNA as information in many many pages (because pages also contain letter and DNA is made up of 4 bases/letter codes). Genes would then be books (with a beginning and an end, those pages of information arranged in a specific way to tell a story, or to give a command in the case of genes) and the chromosomes would represent libraries where collections of these books (all with different stories/messages) would exist in a very orderly environment. Like with our own libraries, chromosomes also have a labeling system of its own and each gene, just like each book in our libraries, has a specific place in the chromosome it belongs to. Chromosomes exist in order to help molecules inside our cells find the genes they need in order to make more DNA or to send of messages read/made from a specific gene.
24Genes hold the key to heredity A gene is a short segment of DNA that contains the instructions for how to make one (or more) proteins.Each protein carries out a specific function within our body.MS, HS – LS3A
25Chromosomes and Inheritance Paired UpSutton studied grasshoppercells through a microscope. He concluded that genes are carried on chromosomes.
26Chromosomes and Inheritance A Pair of ChromosomesChromosomes in a pair may have different alleles for some genes and the same allelesfor others. Is the organism homozygous or heterozygous?
27Chromosomes and Inheritance MeiosisDuring meiosis, a cell produces sex cells with half the number of chromosomes. The correct number is restored when sperm and eggs combine!