Download Free Medical Classical Mendelian Genetics PowerPoint Presentation

Classical Mendelian Genetics PowerPoint Presentation

DOWNLOAD MEDICAL POWERPOINT PRESENTATION

About This Presentation

Description : Check out this medical presentation on Genetics, which is titled "Classical Mendelian Genetics", to learn about genetics and heredity, and classical mendelian genetics.

Tags : Genetics, Classical Mendelian Genetics, heredity

Published on : Aug 29, 2021 | Views : 2233 | Downloads : 0

Shareable Url :

Embed Code :

Comment

Transcript

Slide 1-

Classical Mendelian Genetics Biology-Unit 13
Slide 2-

Definition of Genetics Branch of Biology that studies the ways in which hereditary information is passed on from parents to offspring. Genetics as a science was first practiced by Gregor Mendel Mendel was an Austrian monk who experimented for many years with pea plants
Slide 3-

Mendel (cont.) Before his experiments, people believed that “factors” were inherited as a blend of Mom and Dad’s “factors”
Slide 4-

Mendel (cont.) Why Peas? Mendel used peas to study inheritance because: True breeding strains were available Peas are easy to grow and maintain They have a short generation time
Slide 5-

Mendel (cont.) Peas have many easy to observe traits including: Seed color - Green or yellow Seed shape - Round or wrinkled Pod color - Green or yellow Pod shape - Smooth or constricted Flower color - White or purple Flower position - Axial or terminal Plant size - Tall or dwarf
Slide 6-

Mendel (cont.) Pea flowers are constructed in such a way that they typically self fertilize Because of this, it is relatively easy to control crosses in peas By removing the anthers of one flower and artificially pollinating using a brush, crosses can be easily controlled in peas.
Slide 7-

The seven pea characteristics studied by Mendel Flower Color Flower Position Seed Color Seed Shape Pod Shape Pod Color Plant Height Dominant Recessive
Slide 8-

Mendel’s First Experiment P generation – (parental) true-breeding F1- (first filial) offspring of P generation F2 – (second filial) offspring from F1 cross
Slide 9-

Mendel’s First Experiment In this breeding experiment, Mendel cross-pollinated (hybridized) two contrasting, true-breeding pea varieties. Mendel would then allow the F1 hybrids to self-pollinate to produce an F2 generation.
Slide 10-

Mendel’s First Experiment When Mendel allowed the F1 plants to self-fertilize, the F2 generation included both purple-flowered and white-flowered plants. The white trait, absent in the F1, reappeared in the F2.
Slide 11-

Mendel’s Results When crossing purple flowered peas with white flowered peas, Mendel got the following results: In the first filial (F1) generation all offspring produced purple flowers In the second generation (second filial or F2) approximately a 3:1 ratio of purple to white flowers was seen
Slide 12-

Mendel’s Results Because the F1 generation did not produce light purple flowers and because white flowers showed up in the F2 generation, Mendel disproved blended inheritance. Mendel said that the parents had two sets of factors (genes), thus two copies of the flower color gene Each gene has two varieties-called alleles In the case of the flower color gene, the two alleles are white and purple
Slide 13-

Mendel’s Results In the F1 generation, the white allele was hidden by the purple “dominant” allele In the F2 generation, 1/4 of the offspring wound up with two copies of the white allele, thus they were white Mendel termed this discovery “The Law of Dominance”
Slide 14-

Mendel’s First Law: The Law of Dominance If only one of the genes in a pair is expressed, it is called the dominant allele The gene which is present but not expressed is called the recessive allele Recessive alleles may be hidden and not shown for many generations When two copies of a recessive allele are present then the recessive trait will show
Slide 15-

Mendel’s 2nd Law-The Law of Segregation The two alleles for each character segregate (separate) during gamete production
Slide 16-

Mendel’s 2nd Law-The Law of Segregation
Slide 17-

Mendel’s 3rd Law-The Law of Independent Assortment When Mendel crossed peas and looked at two different traits, he discovered that the traits assorted independently In other words, if he was looking at the height of the plants and the color of the flowers, all four possible combinations of height and flower color were produced: Tall Purple Tall white Dwarf Purple Dwarf white
Slide 18-

Mendel’s 3rd Law-The Law of Independent Assortment As long as genes are on different chromosomes, they will assort independently This meant that a seed’s color did not depend on its shape, nor did height of the plant affect the flower color
Slide 19-

Mendelian Genetics Vocabulary Character –heritable feature Trait – each variant for a character Dominant Allele: a gene that exerts it’s full effect no matter what effect it’s allelic partner may have. The dominant allele is represented by a capitalized letter (ex. T=tall)
Slide 20-

Mendelian Genetics Vocabulary Recessive Allele: a gene that is masked by the dominant allele The recessive allele is represented by the same letter but lower case (ex. t=short) Remember: Diploid organisms have 2 copies of every gene, therefore they have 2 alleles for a specific trait
Slide 21-

Mendelian Genetics Vocabulary Homozygous: an organism that contains identical alleles (ex. TT or tt) Also called pure-bred Homozygous parents can only pass one form of an allele to their offspring. R R R R
Slide 22-

Mendelian Genetics Vocabulary Heterozygous: an organism that contains two different alleles (ex. Tt) Also called hybrid Heterozygous parents can pass either of two forms of an allele to their offspring.
Slide 23-

Mendelian Genetics Vocabulary Genotype: genetic make-up of an organism or the specific alleles represented by letters ex. tt, TT, Tt Phenotype: the observable appearance of an individual resulting from it’s genotype ex. Tall, short, yellow
Slide 24-

Solving Genetic Problems Involving Different Types of Inheritance The Key Steps 1.) decide the type of inheritance involved 2.) choose a capital letter for the dominant trait – it’s lower case for the recessive counterpart 3.) decide your mating (cross) 4.) construct a “Punnett” Square to describe results of mating 5.) be sure to answer the question(s) posed in the problem
Slide 25-

Making A Punnett Square White Flower Parent (pp) Purple Flower Parent (PP) Gametes p p P P
Slide 26-

Basic Types of Inheritance + Genetic Crosses A.) Simple Dominance – One trait dominates over a second 1.) Test Cross – Used to determine whether an organism is homozygous or heterozygous. Test organism is crossed to a pure recessive.
Slide 27-

Basic Types of Inheritance + Genetic Crosses Double cross-Looking at the inheritance of two separate traits. If both organisms are hybrid for both traits this becomes a “dihybrid-cross” Mendel noticed that whenever two dihybrids are crossed, the ratio of the genotypes is 9:3:3:1
Slide 28-

Incomplete Dominance When traits are crossed and a blending of the dominant and recessive phenotypes takes place.
Slide 29-

Basic Types of Inheritance + Genetic Crosses C.) Co-Dominance (Multiple Alleles) – Two or more alleles both show over a third (human blood types) D.) Sex-Linkage – Traits are carried only on the sex chromosomes
Slide 30-

Genetics and People Genetic Diseases 1. sickle cell anemia Production of abnormal, crescent shaped red blood cells. It is autosomal (not in the sex pair) and recessive (you can be normal, a carrier, or have the disease) caused by malformed hemoglobin blood loses the ability to carry oxygen red blood cells can stick to sides of blood vessels and cause a clot
Slide 31-

ppt slide no 31 content not found
Slide 32-

Genetics and People 2. Tay-Sachs disease: It destroys the nervous system of children. They usually do not live beyond the age of four. It is autosomal and recessive (you need 2 copies to have the disease) common in Jews of eastern European descent
Slide 33-

Genetics and People 3. PKU (phenylketonuria): It is an inherited condition of severe mental retardation due to a failure to breakdown phenylalanine, an amino acid. It is autosomal and recessive. Brain fails to develop during infancy Can be prevented by eating a diet free of phenylalanine All newborns are screened for this disease
Slide 34-

Genetics and People 4. Cystic fibrosis A respiratory disorder caused by excessive production of thick mucus in the lungs and pancreas. Autosomal and recessive.
Slide 35-

Genetics and People 5. Thalassemia: A severe form of anemia (loss of red blood cells). It is autosomal and recessive. 6. Huntington’s Disease: An incurable form of insanity that starts at age 40. It is autosomal and dominant.
Slide 36-

Genetics and People 7. Hemophilia- a sex-linked recessive disease Blood is missing a protein which allows it to clot properly Genetic engineering has led to manufacture of this protein and better treatment
Slide 37-

Genetics and People B. genetic screening 1. Amniocentesis: a sample of amniotic fluid is genetically analyzed.
Slide 38-

Genetics and People 2. Karyotype: an enlarged photograph of arranged human chromosomes.
Slide 39-

Genetics and People 3. Genetic Counseling: when high risk groups are tested for and advised on possible genetic disorders of their offspring. Examples: genealogies or family pedigrees
Slide 40-

Genetic Applications A. Plant and animal breeding: breeders apply the principles of genetics to improve plants and animals. Breeding Methods: 1. Artificial Selection: plants or animals having desired qualities are selected to reproduce their kind. Examples: horse and dog breeders
Slide 41-

Genetic Applications 2. Hybridization Crosses are made between organisms having desirable qualities in the attempt to produce some offspring that incorporate these qualities. Examples: American cattle and Brahman cattle
Slide 42-

Genetic Applications 3. Inbreeding Is the mating of organisms of the same strain or type Example: German shepherds will only be bred with German shepherds Problem: offspring are more susceptible to diseases and have shorter life spans.
Slide 43-

Genetic Applications 4. Vegetative Propagation Desirable traits in plants can be easily produced by asexual means. Example: seedless fruits
Slide 44-

Heredity and Environment Both the genetics and the environment affect the phenotypes and development of organisms.
Slide 45-

Heredity and Environment 1. Effect of Temperature on hair color in the Himalayan rabbit Himalayan rabbits are white except for its black nose, ears, tail, and feet. In experiments, fur was removed from the rabbits back, an ice pack was applied while the fur grew back.
Slide 46-

Heredity and Environment This low temperature produced black fur. Conclusion: low temperature prevents the action of the white fur gene and enzyme.