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Data for Students from 2014/2015
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Data for Students from 2014/2015
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Data for Students from 2014/2015
Trait 347 348 349 Hand Clasping Left on top 16 13 14 Right on top 17 15 Cleft Chin yes 20 19 Cleft Chin no 10 9 Hair on middle finger No hair on middle finger Right handed Left handed
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2016-2017 Results Trait 347/348 347/348 LE 349/351 LE Eye Color Blue
Eye Color Blue Brown Gray Green Hazel Tongue Rolling Yes Tongue Rolling No PTC Yes PTC No Widow’s Peak Straight Hairline Attached Earlobe Detached Earlobe Cheek Dimples No Cheek Dimples
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Trait 347/348 347/348 LE 349/351 LE Left Thumb on Top Right Thumb on Top Cleft Chin (Dimple) Smooth Chin Middle Finger Hair No Middle Finger Hair Right Handed Left Handed Normal Thumb Hitchhiker Thumb
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LT- Today, I can connect my observations of human traits to Gregor Mendel’s studies by comparing what I have found in my investigation to his pea plant experiments. Are there trends in the human traits data that we are collecting? Is there a relationship between our data and Mendel’s data?
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Human Chromosomes 46 chromosomes 23 pairs
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Chromosomes come in pairs. Chromosome pair 2 Mom Dad
Remember: Chromosomes come in pairs. Chromosome pair 2 Mom Dad Eye Color The genes along the chromosomes code for the same gene, but can be a different variation of the trait.
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For all traits, you have two genes (one came from mom and the other from dad)
Allele- one of two alternate or similar forms of a gene. Ex) In your DNA, you may have an allele for brown hair and an allele for blond hair. Or you may have 2 alleles for blond hair. Or 2 alleles for brown hair. When genes pair up, there are different relationships that they could have with each other:
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Labrador Retrievers ? Purebred
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Huskies Purebred
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Labrador and a Husky Hybrid
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Purebred= has no variation for a trait
Purebred= has no variation for a trait. For example, a plant that can only produce offspring with purple flowers. Or a plant that can only produce offspring with white flowers. Hybrid= has variation for a trait. For example, a plant that can produce offspring with purple and white flowers.
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Are these alleles examples of purebred or hybrid. 1. EE 2. ee 3. Ee 4
Are these alleles examples of purebred or hybrid? 1. EE 2. ee 3. Ee 4. Dd 6. DD 7. dd
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Gregor Mendel Mendel's pea plant experiments conducted between 1856 and 1863 established many of the rules of heredity, now referred to as the laws of Mendelian inheritance. Mendel noticed: Some traits show up more frequently than others. Some traits seemed to be passed from parents to offspring , while others did not seem to be (meaning the parents did not appear to have the trait).
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Pea Plant Experiments Trying to get answers as to why these trends occurred amongst traits, Gregor decided to experiment with pea plants. Why pea plants, you ask? When pea plants are bred, the offspring grow into adulthood quickly. Therefore, he could observe the traits of many generations of pea plants.
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Let’s look at what he did!!!!!
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Homework: Define in your notebook: Genotype Phenotype Dominant Allele Recessive Allele Homozygous Dominant Homozygous Recessive Heterozygous Introduction to Mendelian Genetics Lab” questions 1- Extension 1.
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Mendel bred a purebred purple flower with a purebred white flower.
Let’s give his flowers letters for the alleles Let’s use P for purple and W for white. What do you think the flower color of the offspring were? What percent were purple versus white? Why? What do you think the alleles are for these offspring? Mendel then bred hybrids (PW) flowers.
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Recreate the experiment on the “Gregor Mendel’s Pea Plant Flower Experiment” sheet. Including the 2 questions that you have about the outcome of his experiments. Print it. One for each partner. Color in the flowers. Give in to me. I will review it and make comments. You fix mistakes.
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One of Mendel’s Experiments:
He bred a purebred purple flower with a pure purebred white flower. The offspring only had purple flowers. Unusual????????? These offspring are hybrids because they have one parent with purple flowers and the other with white. He then bred two hybrids. In the second generation (the offspring of the hybrids), there was a mix of purple and white But, on average, there were more purple than white when two hybrids were bred. The ratio was 75% purple to 25% white.
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Why do we notice trends that occur in Mendel’s experiments and in our inventory of traits?
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What are the trends that we noticed in our data
What are the trends that we noticed in our data? Some variations of a trait show up more frequently. For Example, brown eyes show up more frequently than blue eyes. What are the trends that Mendel noticed in his data? For example, purple flowers show up more frequently than white in pea plants. Now we have to find out why!!!!
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What questions do you have
What questions do you have? Why do some variations of a trait show up more frequently than others? Why do some traits show in the offspring but not the parents? Why does the F1 generation have only one variation of the trait? Why is there a 75% 25% ratio in the F2 generation? What do you think Mendel’s experiments proved or showed? Mendel’s studies gave some answers to the above questions. Is there a relationship between Mendel’s data and your data? The relationship between Mendel’s data and my data is that in his pea plant studies there are variations of a trait that are more common which is what we discovered in the inventory of our classmates traits.
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The traits such as the flower color of Mendel’s pea plants are known as: Inherited traits- Traits that are passed from parent to offspring. Exactly how do parents pass on traits to their offspring? Gene- an inherited bit of information that is passed directly from parents cells to offspring cells. Genes are found along a DNA strand (i.e.- a DNA strand is made up of a sequence of genes that are codes for different traits) What if a trait is not passed from parent to offspring? How does one get a trait that is not inherited? Non-inherited Trait- learned traits or physical traits that we acquire from the environment.
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The genotype of blue eyes may look like this: ATGCTAG
Genotype- the genetic makeup of an organism (What is found on the DNA). We use capital and lowercase letters to express genotype. The genotype of blue eyes may look like this: ATGCTAG TACGATC Phenotype- what an organism looks like as a result of its genotype (physically or behaviorally shows). We use character descriptions to express phenotype. Blue eyes physically showing is the phenotype
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Mendelian Genetics Sometimes genes can be dominant and recessive
Mendelian Genetics Sometimes genes can be dominant and recessive. Dominant Gene (allele)- A variation of a trait that is stronger and masks a weaker trait. Capital letters are used to represent dominant genes. We use capital letters to represent a dominant trait. Example: Brown Eyes= E If this trait is present in an individuals DNA, it will show up as a physical characteristic of that individual. Recessive Gene (allele)- A variation of a trait that is weaker and is masked by a stronger trait. Lower case letters are used to represent recessive genes. We use lower case letters to represent recessive traits. Example: Blue Eyes= e If this trait is present in an individuals DNA, it will not always show up as a physical characteristic. It will only show if the person’s alleles are both this trait.
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Homozygous- two of the same alleles for a gene
Homozygous- two of the same alleles for a gene. TT or tt Homozygous dominant- TT alleles are identical and dominant. Homozygous recessive- tt alleles are identical and recessive. Heterozygous- two different alleles for a gene. Tt alleles are different.
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Mendel’s experiments were done mostly on pea plants
Mendel’s experiments were done mostly on pea plants. Understanding why pea plants have purple vs. white flowers doesn’t seem important to the average person, DOES IT? Why should we care about Mendel’s studies? The next video is one of many examples of why Mendel’s studies are important to all of us, not just those who study or practice science.
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Genetic Disease/Disorder-
An inherited disease or disorder that caused by a mutation in a gene or by a chromosomal defect.
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LT- Today, I can apply my understanding of the relationship between allele pairs by comparing and contrasting dominant and recessive, codominant, and incomplete dominant alleles as I create my own critter pup. What is the phenotype outcome when both the dominant and recessive alleles are in an individual’ s genotype?
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Mendelian Genetics Dominant and Recessive Alleles Example Trait= Human Hair Color Brown Hair (B) Blonde Hair (b) Genotype Phenotype BB Brown bb Blonde Bb
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When sex cells (sperm and egg) are being made, it is like the toss of a coin for which allele will go into the sex cell. It’s a 50/50 chance. But remember, a parent can only give a variation of an allele that they have in their genotype- YOU CAN’T GIVE SOMETHING YOU DO NOT HAVE TO GIVE!!!
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What are non-Mendelian traits. What are codominant traits
What are non-Mendelian traits? What are codominant traits? What are incomplete dominant traits?
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Non-Mendelian Genetics When different alleles that we inherit from our parents come together they can have different relationships:
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Codominant Alleles Example Trait= Certain Horse breeds fur color Black (B) White (W)
Genotype Phenotype BB Black WW White BW Black and White Spots
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Incomplete Dominant Alleles Example Trait= Certain Rabbit breeds fur color Black (B) White (W)
Genotype Phenotype BB Black WW White BW Grey
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Dominant and Recessive Alleles One allele is dominant over the other
Dominant and Recessive Alleles One allele is dominant over the other. When they are in an individual’s genotype together the dominant allele shows in the phenotype. Codominant Alleles The 2 alleles are equally dominant. When they are in an individual’s genotype together they both show in the phenotype but separately. This could be in the form of spots, stripes, etc. We use two different capitalized letters to represent the alleles. Incomplete Dominant Alleles The 2 alleles are equally dominant. When they are in an individual’s genotype together they both show in the phenotype, but they make a third trait by blending.
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