* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Genetics PowerPoint - Lewiston School District
Survey
Document related concepts
Minimal genome wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Heritability of IQ wikipedia , lookup
Genome (book) wikipedia , lookup
Gene expression profiling wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Genomic imprinting wikipedia , lookup
Population genetics wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Hardy–Weinberg principle wikipedia , lookup
Genetic drift wikipedia , lookup
Designer baby wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Transcript
Genetics Genetics • Focus Question: – If most organisms start from a single cell, than why don’t we all look the same? • Prediction: – Why do you think species of organisms have different characteristics. For example I have blue eyes, but both of my parents have light green eyes. The Father of Genetics • The study of genetics is a very complicated and technical process, but the basic principal is quite simple. An Austrian Botanist is considered to be known as the “Father of Genetics” because of what he learned from his scientific experiments with pea pod plants. • In the mid 1800’s Gregor Mendel carefully studied seven traits of the pea plant; seed shape, seed color, flower position, pod shape, seed coat color, stem length, and pod color. He discovered that crossing two plants with the same trait did not guarantee that those traits would show in their offspring. He discovered that if there were different traits in the plants’ history, those traits might eventually show up. Pea Pod Experiment Mendel discovered that living organisms pass down traits to their offspring that do not physically show up from generation to generation. Mendel could not prove why this happened at the time, but it did set the stage for further investigation. Physical traits are observable characteristics determined by specific segments of DNA called genes. Multiple genes are grouped together to form chromosomes, thread-like parts which are found in the nucleus of the cell. Genes carry the information that determines the traits of an organism. Basic Animal Cell Chromosomes Nucleus •A chromosome is an organized package of DNA found in the nucleus of the cell. Different organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes. Each parent contributes one chromosome to each pair so that offspring get half of their chromosomes from their mother and half from their father An example of possible variations A Gene •The gene is the basic physical unit of inheritance. They are arranged, one after another, on the chromosomes and contain the information needed to specify traits. Humans have approximately 23,000 genes arranged on their chromosomes. a A A Allele •An allele is one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent. So How does Mendel's Peas Explain how we Inherit our Traits? • If you think back to our cell investigation we said that organisms begin as one cell. • Because of the way cells divide and join during reproduction, each new offspring created receives chromosomes (multiple groups of genes) for specific traits from the male and from the female. • • Parent 1st Generation The example to the right demonstrates how Mendel’s pea pods could pass down genes for the specific trait of color. From this we discovered that some genes are recessive and some genes are dominate. 2nd Generation Recessive and Dominate Genes We discovered that some genes are recessive and some genes are dominate because most genes have two or more variations, called alleles Parent Alleles: The variation of genes for a trait. The alleles for the color of a pea are referred to as G: green and Y: yellow. The green parent received 2 green alleles The yellow parent received 2 yellow alleles In this example each parent gives their offspring a copy of one of their alleles. Depending on what allele variations parents have to offer, offspring may inherit two identical or two different alleles. In this case each parent only had one type of allele to offer, one G and one Y As a result, all new 1st generation offspring are yellow because the alleles interact in what is called a dominant or a recessive manner. 1st Generation Recessive and Dominate Traits Dominate Traits: The trait observed because a dominant allele is present in the genes that the offspring received from its parents. Parent In this example yellow color is a dominate trait Recessive Traits: Traits due to recessive alleles are only observed when two recessive alleles are present. Recessive alleles may exist in the genes of the offspring but the trait is not observed. 1st Generation In this example green is a recessive trait Depending on which alleles (gene variation) a pea receives, future offspring could be green although both parents are yellow. If you cross the 1st generation of peas again, the second generation could receive any of the following allele combinations. 2nd generation offspring could be yellow or green. 2nd Generation Inherited Traits • You inherit many kinds of traits from your parents that determine your physical features. Many of these traits cannot be changed and may not even be present in your parents or grand parents because they are recessive genes. •You are born with most of your traits, but some such as intelligence, personality, and athletic ability, may be inherited to a certain extent, but you are greatly influenced by your environment and your attitude. For example; If your parents were straight “A” students or professional athletes, you are not going to be just because you have their genes. Inherited Traits •There are thousands of genes that determine the traits each person has. We know that these traits are inherited from our parents and we know that some are dominate and some are recessive. •Most physical traits result from a mix of genes, but scientists believe that some traits are due to one gene. When more than one gene determines a trait it is very difficult to predict an inheritance pattern. For example Mendel couldn’t easily predict the height and weight of pea pods, but he could predict their color. This chart contains traits that scientists have been able to study and predict inheritance patterns. You would assume that dominant alleles are the most common in a population, but we are going to complete an investigation to find out if this is always true. Record the following in your scientist notebook • What are examples of recessive and Dominate traits? Create a large version of this table below. For each of the traits we are going to identify and record the following: Each step will be •What is the Recessive or Dominate Trait? explained in the next •Fraction of Students With the Trait: slides •Fraction of Students Without the Trait: •Most common or least common in our population? Hairline Shape Earlobe Attachment Tongue Rolling Cleft Chin Dimples Handedness Freckles Naturally Curly Hair Hand Clasping Hairline Shape Hairline shape is reportedly due to a single gene with a widow’s peak dominant and a straight hairline recessive. Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students With Widow Peak: •Fraction Students Without Widow Peak: •Most common or least common in our population? This image shows the possible combinations of alleles you could have received from your parents. The only way you can get a straight hairline is if both your parents gave you a recessive allele. Earlobe Attachment Some scientists have reported that this trait is due to a single gene for which unattached earlobes is dominant and attached earlobes is recessive. Results of Allele Combinations U is the Dominate Allele u is the recessive Allele Unattached = UU Unattached = Uu If earlobes hang free, they are detached. If they attach directly to the side of the head, they are attached earlobes. Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students With unattached earlobes: •Fraction Students With attached earlobes : •Most common or least common in our population? Detached = uu These are the possible combinations of alleles you could have received from your parents. If you have detached earlobes, both your parents gave you a recessive allele. Tongue Rolling Tongue rolling ability may be due to a single gene with the ability to roll the tongue a dominant trait and the lack of tongue rolling ability a recessive trait. Results of Allele Combinations R is the Dominate Allele r is the recessive Allele Can Roll = RR Can Roll = Rr Can’t Roll = rr Can you roll your tongue? Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students who can role tongue: •Fraction Students who can’t role tongue: •Most common or least common in our population? These are the possible combinations of alleles you could have received from your parents. If you can’t roll your tongue, both your parents gave you a recessive allele. Cleft Chin This trait is reportedly due to a single gene with a cleft chin dominant and a smooth chin recessive. Results of Allele Combinations C is the Dominate Allele s is the recessive Allele Cleft Chin = CC Cleft Chin = Cs Smooth Chin = ss Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students With Cleft Chin: •Fraction Students Without Cleft Chin: •Most common or least common in our population? These are the possible combinations of alleles you could have received from your parents. If you have a smooth chin, both your parents gave you a recessive allele. Dimples Dimples are reportedly due to a single gene with dimples dominant (people may exhibit a dimple on only one side of the face) and a lack of dimples recessive. Results of Allele Combinations D is the Dominate Allele d is the recessive Allele Dimples = DD Dimples = Dd No Dimples = dd Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students With Dimples: •Fraction Students Without Dimples: •Most common or least common in our population? These are the possible combinations of alleles you could have received from your parents. If you have no dimples, both your parents gave you a recessive allele. Handedness Some scientists have reported that handedness is due to a single gene with right handedness dominant and left handedness recessive. However, other scientists have reported that the interaction of two genes is responsible for this trait. Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students who are Right Hand Dominate: •Fraction Students who are Left Hand Dominate: •Most common or least common in our population? Results of Allele Combinations R is the Dominate Allele l is the recessive Allele Right Handed = RR Right Handed = Rl Left Handed = ll These are the possible combinations of alleles you could have received from your parents. If you are left handed, both your parents gave you a recessive allele. Freckles This trait is reportedly due to a single gene; the presence of freckles is dominant, the absence of freckles is recessive. Results of Allele Combinations F is the Dominate Allele f is the recessive Allele Freckles = FF Freckles = Ff No Freckles = ff Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students With Freckles: •Fraction Students Without Freckles: •Most common or least common in our population? These are the possible combinations of alleles you could have received from your parents. If you have no freckles, both your parents gave you a recessive allele. Naturally Curly Hair Early geneticists reported that curly hair was dominant and straight hair was recessive. More recent studies suggest that more than one gene may be involved. Results of Allele Combinations C is the Dominate Allele s is the recessive Allele Curly = CC Curly = Cc Straight = ss Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students With Curly Hair: •Fraction Students Without Curly Hair: •Most common or least common in our population? These are the possible combinations of alleles you could have received from your parents. If you have straight hair, both your parents gave you a recessive allele. Hand Clasping A study of identical twins concluded that hand clasping has at least some genetic component. However, other scientists have not found evidence that genetics plays a significant role in determining this trait. Fold your hands together by interlocking your fingers without thinking about it. Which thumb is on top – your left or your right? Record and label in your table: •What is the Recessive or Dominate Trait? •Fraction Students with Left Thumb on Top: •Fraction Students with Right Thumb on Top: •Most common or least common in our population? One study found that 55% of people place their left thumb on top and 45% place their right thumb on top. 1% have no preference. I was not able to find evidence that supports whether one is a dominate or recessive allele. Our Class Data: Hairline Shape Widows Peak Dominate _______ Widows Peak _______ No Widows Peak Earlobe Attachment Unattached is Dominate _______ Unattached _______ Attached Tongue Rolling Tongue Rolling Dominate _______ Roll Tongue _______ Can’t Roll Tongue Which is most common in our Classroom Population? Which is most common in our Classroom Population? Which is most common in our Classroom Population? Cleft Chin Cleft Chin Dominate _______ Cleft _______ No Cleft Dimples Dimples Dominate _______ Dimples _______ No Dimples Handedness Right Hand is Dominate Trait _______ Right Handed _______ Left Handed Which is most common in our Classroom Population? Which is most common in our Classroom Population? Which is most common in our Classroom Population? Freckles Freckles are Dominate Trait _______ Freckles _______ No Freckles Naturally Curly Hair Curly Hair Dominate Trait _______ Curly Hair _______ Straight Hair Hand Clasping Dominate vs. Recessive??? _______ Left Thumb _______ Right Thumb Which is most common in our Classroom Population? Which is most common in our Classroom Population? Which is most common in our Classroom Population? Does the dominate trait express itself more frequently then the recessive? Classroom A Data: Hairline Shape Widows Peak Dominate 8/21 Widows Peak 13/21 No Widows Peak Earlobe Attachment Unattached is Dominate 14/21 Unattached 7/21 Attached Tongue Rolling Tongue Rolling Dominate 17/21 Roll Tongue 4/21 Can’t Roll Tongue No Widows Peak Frequent Unattached Most Frequent Rolling is Most Frequent Cleft Chin Cleft Chin Dominate 6/21 Cleft 15/21 No Cleft Dimples Dimples Dominate 11/21 Dimples 10/21 No Dimples Handedness Right Hand is Dominate Trait 14/15 Right Handed 1/15 Left Handed No Cleft Most Frequent Dimples Most Frequent Right Handed Appeared More Freckles Freckles are Dominate Trait 13/17 Freckles 4/17 No Freckles Naturally Curly Hair Curly Hair Dominate Trait 3/17 Curly Hair 14/17 Straight Hair Hand Clasping Dominate vs. Recessive Unsure??? 8/15 Left Thumb 7/15 Right Thumb Freckles Appeared Most Straight Hair Appeared the Most Classroom B Data: Hairline Shape Dominate: Widows Peak Recessive: Straight Line 13/25 Widows Peak 12/25 Straight Line Earlobe Attachment Dominate: Unattached Recessive: Attached 15/25 Unattached 10/25 Attached Tongue Rolling Dominate: Can Recessive: Can’t 18/25 Can 7/25 Can’t Widows Peak Showed Most Unattached Showed Most Can Showed Most Cleft Chin Dominate: Cleft Recessive: No Cleft 5/25 Cleft 20/25 No Cleft Dimples Dominate: Dimples Recessive: No Dimples 16/25 Dimples 9/25 No Dimples Handedness Dominate: Right Recessive: Left 22/24 Right Handed 2/24 Left Handed No Cleft Showed Most Dimples Showed Most Right Showed Most Freckles Dominate: Freckles Recessive: No Freckles 19/24 Freckles 5/24 No Freckles Naturally Curly Hair Dominate: Curly Recessive: Straight 8/24 Curly 16/24 Straight Hand Clasping Dominate vs. Recessive Unsure?? 13/24 Left 11/24 Freckles Showed Most Straight Showed Most Left Showed Most Answer the following questions in your scientist notebook Use the data you collected from the table… •Did most of the students in your class display dominate or recessive traits? Why do you think this happened? •Do you think the results would be different if you had surveyed the whole school? Explain your opinion… •Do you think the results would be different if you surveyed people from different parts of the country or world? Explain your opinion… Claims and Evidence • Focus Question: – If most organisms start from a single cell, than why don’t we all look the same? I claim that… I claim this because… Conclusion • Revisit your original prediction and explain whether the evidence from our investigation supports it or not. Reflection • Respond to some of the following – What really surprised you – What new questions do you have – What would you really like to know more about