MENDELIAN INHERITANCE.Dpptx in science 9

MENDELIAN INHERITANCE POWERPOINT PRESENTATION IN SCIENCE 9

1. MENDELIAN INHERITANCE

2. Who is Gregor Mendel? Gregor Mendel is an Austrian monk, scientist and teacher who is considered as the father of genetics. He was the first one to set the primary tenets relating to the transmission of traits from parents to offspring thru his experiment using garden pea plant.

3. FUNDAMENTAL LAWS OF INHERITANCE LAW OF SEGREGATION - during gamete formation, the allele for each gene segregates or separates from each other such that each gamete formed carries only one allele.

4. FUNDAMENTAL LAWS OF INHERITANCE 2. LAW OF INDEPENDENT ASSORTMENT - genes for different traits assort independent of each other during genetic formation; - a trait does not affect the inheritance of another trait.

5. FUNDAMENTAL LAWS OF INHERITANCE 3. LAW OF DOMINANCE - the presence of a dominant allele conceals, masks or prevents the expression of the recessive allele. Dominant – trait that is always expressed; represented by capital letter. Recessive – trait always masked by the dominant trait; represented by small letter.

6. HOMOZYGOUS AND HETEROZYGOUS Homozygous – term used to refer to organism that has two identical alleles for a particular trait. Homozygous dominant Homozygous recessive Heterozygous – term used for organism that has two different alleles for the same gene.

7. GENOTYPE AND PHENOTYPE Genotype – the genetic make up of an organism; description of the genes present in an organism. Phenotype – the physical characteristics that an organism manifests/show.

8. PUNNETT SQUARE Grid that enables one to predict the outcome of simple genetic crosses; Simulates two organisms reproducing sexually, examining just one of the many genes that get passed on. - the completed square shows every possible way the offspring could inherit this gene, and what the chances are for each result.

9. STEPS IN PERFORMING PUNNET SQUARE: 1. Name the alleles involved. Choose a letter to represent the alleles. Write the dominant allele with any capital letter, and the recessive allele with the same letter in lowercase. SAMPLE PROBLEM: In guinea pigs, short hair is dominant over long hair. What type of offspring do you expect if you crossed a homozygous short haired guinea pig to a homozygous long haired one?

10. STEPS IN PERFORMING PUNNET SQUARE: 2. Check each parent’s genotype for the trait. 3. Draw a 2x2 square. Leave room above the box and to its left. 4. Label the rows with one parent’s genotype and the columns with the other parent’s genotype. Separate the alleles of the parents in each row or column. 5. Complete the Punnet Square by having each box combine the letters from its rows and column. If there is a dominant allele, write it first before the recessive one.

11. STEPS IN PERFORMING PUNNET SQUARE: 6. Interpret the Punnett Square by determining the genotype and phenotype. What if we cross bred 2 heterozygous shorthaired guinea pigs, what will be the resulting offspring?