Course: Animals Production. Unit Title: Genetics TEKS: 130.3(C)(6)(B) Instructor: Ms. Hutchinson. Objectives:

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1 Course: Animals roduction Unit Title: Genetics TEKS: 130.3(C)(6)() Instructor: Ms. Hutchinson Ojectives: After comleting this unit of instruction, students will e ale to: A. Exlain Gregor Mendel s contriution to the scientific community;. Descrie the interaction etween chromosomes, genes, traits, and alleles; C. Differentiate etween genotye and henotye; D. List the 6 fundamental tyes of mating; E. Workout unnett squares for one and two air of contrasting traits; and F. Calculate henotyic and genotyic ratios.

2 Interest Aroach: Many of your traits, including the color and shae of your eyes, the texture of your hair, and even your height and weight, resemle those of your arents. The assing of traits from arents to offsring is called heredity. Humans have long een interested in heredity. From the eginning of recorded history, we have attemted to alter cro lants and domestic animals to give them traits that are more useful to us. efore DNA and chromosomes were discovered, heredity was one of the greatest mysteries of science. The scientific study of heredity egan more than a century ago with the work of an Austrian monk named Gregor Mendel. Mendel carried out exeriments in which he red different varieties of garden eas. ritish farmers had erformed similar reeding exeriments more than 200 years earlier. ut Mendel was the first to develo rules that accurately redict atterns of heredity. The atterns that Mendel discovered form the asis of genetics, the ranch of iology that focuses on heredity. Mendel s arents were easants, so he learned much aout agriculture. This knowledge ecame invaluale later in his life. As a young man, Mendel studied theology and was ordained as a riest. Three years after eing ordained, he went to the University of Vienna to study science and mathematics. There he learned how to study science through exerimentation and how to use mathematics to exlain natural henomena. Mendel later reeated the exeriments of a ritish farmer, T.A. Knight. Knight had crossed a variety of the garden ea that had urle flowers with a variety that had white flowers. All of the offsring of Knight s crosses had urle flowers. However, when two of the urle-flowered offsring were crossed, their offsring showed oth white and urle flowers. The white trait had reaeared in the second generation. Mendel s exeriments differed from Knight s ecause Mendel counted the numer of each kind of offsring and analyzed the data. Quantitative aroaches to science, those that include measuring and counting, were ecoming oular in Euroe. Mendel s method was on the cutting edge of research at the time. Let s now take a closer look at Mendel s work and how it has evolved into what we call Genetics today. Curriculum & Instruction: Curriculum A. Exlain Gregor Mendel s contriution to the scientific community; Gregor Mendel: A) Geneticist who first develoed the rules to redicting the attern of heredity Instruction T Slide 4-5 Who is the father of genetics?

3 1) Monk who did exeriments with eas ) Heredity 1. assing of traits such as coat color, olled or horned, height, etc. from arents to offsring As discussed in the introduction Gregor Mendel was the first to develo the rules for redicting heredity. Heredity is the assing of traits such as coat color, olled, or horned from generation to generation. C) reeding Generations 1. Generation a) arental generation 2. F 1 Generation a) Filial Generation ) 1 st offsring of Generation 3. F 2 Generation a) 2 nd Filial Generation ) offsring of F 1 Generation What is heredity? T Slide 6-7 What is the generation? What is the F1 generation? Mendel used three generations in his exeriment. He named the first the generation for arental Generation or the eginning of the reeding rogram. The first set of offsring from the generation he called the F 1 Generation. The F stands for filial, which in genetics relates to a generation or the sequence of generations following the arental generation. The offsring of this second generation he named the F 2 generation or second filial generation. Mendel s initial exeriments were monohyrid crosses. A monohyrid cross is a cross that involves one air of contrasting traits. For examle, crossing a lant with urle flowers and a lant with white flowers is a monohyrid cross. Mendel carried out his exeriments in three stes. D)3 Stes of Mendel s Exeriment 1. Generation a) Allowed each variety to self ollinate for several generations 1. ensure that all offsring would

4 dislay only one form of a articular trait (flower color) 2. Crossred the two strains of the generation - Recorded Data - Resulted in all urle flowers Ste one. Mendel allowed each variety of garden eas to self-ollinate for several generations. This method ensured that each variety would dislay only one form of a articular trait. For examle, a true-reeding urle flowering lant should roduce only lants with urle flowers in susequent generations. These true-reeding lants served as the arental generation in Mendel s exeriments. The arental generation, or generation, are the first two individuals that are crossed in a reeding rogram. Ste two. Mendel than cross-ollinated two generation lants that had contrasting forms of a trait, such as urle flowers and white flowers. Mendel called the offsring the of the generation the first filial generation, or F 1 generation. He then examined each F 1 lant and recorded the numer of F 1 lants exressed each trait. 3. Allowed the F 1 Generation to self-ollinate a) Resulted in the F 2 Generation ) 1 out of every four flowers was white. Ste three. Finally, Mendel allowed the F 1 generation to self-ollinate. He called the offsring of the F 1 generation lants the second filial generation or F 2 generation. Again each of the F 2 lants was characterized and counted. Each of Mendel s F 1 lants showed only one form of the trait. The contrasting form of the trait had disaeared. ut when the F 1 generation was allowed to self-ollinate, the missing trait reaeared in some of the lants in the F 2 generation. When Mendel crossed urle flowers with white flowers, all of the offsring in the F 1 generation had urle flowers. In the F 2 generation, 705 lants had

5 urle flowers and 224 lants had white flowers. Go With the Flow Moment. You will need lank aer and colored encils or crayons. Have them recreate the flow chart, in five to seven minutes, on overhead numer six. T Slide 8. Descrie the interaction etween chromosomes, genes, traits, and alleles; Traits: A) Chromosomes and Genes are in airs 1. One chromosome is contriuted y each arent 2. Chromosome Locus a) site where a gene is found on a chromosome ) Traits 1. For each inherited trait an individual has, there are two coies of that gene ( 1 from each arent) 2. Genes are what causes traits to aear a) each version is called an allele a) eye color, coat color, marling, rieye area, etc. T Slide 9-10 What is a chromosome locus? What causes traits to aear? ecause chromosomes are in airs, genes are also in airs. The location of a gene in a chromosome is called a locus. For each locus in one of the memers of a air of homologous chromosomes, a corresonding locus occurs in the other memer of that chromosome air. The transmission of genes from arents to offsring deends entirely on the transmission of chromosomes from arents to offsring. Genes are what cause traits to e exressed.

6 For each inherited trait an individual has, there are two genes for that secific trait, one from each arent. Grahic Artist Moment to reconstruct the overhead into their noteooks. Homozygous vs. heterozygous III. Genes Located on Corresonding Homologous Chromosomes may: A) Corresond to each other 1. homozygous ) Differ from each other 2. heterozygous C) Genes on corresonding chromosomes that control the same trait are called alleles The genes located at corresonding loci in homologous chromosomes may corresond to each other or contrast with each other in the way that they control a trait. If they corresond, the individual is said to e homozygous at the locus; if they differ, the individual is said to e heterozygous. Those genes that occuy corresonding loci in homologous chromosomes ut that affect the same character in different ways, lack or red coat color, are called alleles. Genes that are alike and that affect the character in the same way are called identical alleles. Alleles: A) Homozygous ( or ) T Slide 11 What is homozygous? What is heterozygous? What is an allele? T Slide 12

7 1. oth alleles are the same ) Heterozygous () 1. two alleles are different C) The dominant (caital) allele is always exressed when it is resent D) The recessive allele is only exressed when oth coies of the gene are recessive What is an examle of homozygous alleles? What is an examle of heterozygous alleles? The geneticist usually illustrates the genes y alhaetical letters. When the genes at corresonding loci on homologous chromosomes differ, one of the genes often overowers, or dominates, the exression of the other. This allele is called dominant. The allele whose exression is suressed is said to e recessive. The dominant allele is symolized y a caital letter; the recessive allele is symolized y a lower case letter. For examle, in cattle, lack hair color is dominant to red hair color, so we let = lack and = red. Three cominations of the genes are ossile.,, or. oth animals and animals are homozygous for the genes that determine hair color, ut one is homozygous dominant () and the other is homozygous recessive (). The animal that is is heterozygous; it has allelic genes. The only red animal will result from the comination. Kee in mind that dominant genes are not necessarily good nor or recessive genes always ad. C. Differentiate etween genotye and henotye. Genotye vs. henotye: A) Genotye 1. amount, order, and tye of genes an individual has 2. genetic make-u of an individual ) henotye 1. hysical traits an individual ossesses 2. Doesn t take into account masked traits only exressed or dominant traits T Slide 13 What is the genotye? What is the henotye?

8 Review The actual configuration of genes in an animal is called the genotye. For any given trait there are three ossile genotyes AA, Aa, or aa. Genotye is looking at the secific make u of that organism. In contrast henotye deicts the hysical aearance of the animal. henotye is looking at the roader icture. henotye doesn t tell us what traits are masked, the recessive traits; it only deicts the dominant traits that mask the recessive ones. Gregor Mendel is known as the father of genetics. He was the founder of a new way at looking at how traits are assed down that he called heredity. He discovered the existence of dominant and recessive traits. That we get one gene from each arent to make a air of genes that controls a secific trait. He conducted a simle, yet effective, exeriment using eas with white and urle flowers. From this knowledge science made rogress to where it is today. We know that genes are found on chromosomes, and that an individual has airs of chromosomes, one contriuted from each arent. The genes on chromosomes are what control all the traits that make u an organism, from height to eye color. A secific trait is controlled y genes found on a very secific sot of homologous chromosomes known as the locus. If oth genes are the same on oth chromosomes the individual is said to e homozygous; if one of the genes is different it is said to e heterozygous. Genotye is the way geneticists descrie the makeu of an organism. Is it heterozygous or homozygous? Examles of a homozygous gene would e or, and heterozygous would e. henotye is the hysical aearance of an animal. Does it have a lack coat or a red one? henotye doesn t take into consideration the recessive genes that are masked y the dominant ones. Dominant & Recessive Genes T Slide 14 Investigate! (interest for dominant and recessive genes) Have students look at their hands for scars, wrinkles, hair, and veins. (aout 30 seconds) Raise your hand if you have hair aove your knuckles.

9 Good, thank you. The resence of hair aove the knuckles is caused y a dominant allele, H. Those of you who have no hair aove your knuckles, what is your genotye for this trait? (hh is the only ossiility) Under what circumstances could a arent without hair aove their knuckles roduce a child with hair aove their knuckles? (The second arent must have hair aove their knuckles) D. List the 6 fundamental tyes of mating; Monohyrid Crosses A. Three class genotyes 1. Homozygous Dominant = 2. Homozygous Recessive = 3. Heterozygous =. = lack & = Red C. Six ossile crosses: x, x, x, x, x, x Using just this information can you think of a reeding rogram where the recessive gene was used to develo an entirely new reed of eef cattle? (Red Angus is an examle of how a reeding rogram successfully isolated a recessive gene and through careful management used that gene to found a new reed.) T Slide 15 What are the 3 classes of genotyes? What are the 6 ossile crosses? Little rofessor When I say little rofessor I would like each of you to find a artner. Kee in mind that you need to e in airs with an area large enough for oth of your noteooks. Little rofessor. Good jo guys. I now need one erson in each grou to raise your hand. Those of you with your hands u will e Little rofessor I and your artners will e Little rofessor II. Little rofessor II s. For the next coule of minutes you are not to listen to me. You may read, daydream, or ut your head down. The only thing you can t do is leave your seats, talk, or e a disrution. E. Workout unnett squares for one and two air of contrasting traits; and F. Calculate henotyic and genotyic ratios. redicting Ratios:

10 T Slide 16 Homozygous x Homozygous A. Genotye 2. Results in a homozygous dominant zygote. x henotye: 1. Each arent can only contriute a dominant gene Little rofessor I s, you have the next thirty seconds to instruct your artners on this information, e sure they get the most imortant information into their noteooks. Little rofessor I s, it is now your turn to take a reak while I talk with the Little rofessor II s. T Slide 17 Homozygous x Heterozygous E. x 1. Genotyic Ratio 2 : 2 2. henotyic Ratio

11 a) 4 lack color Little rofessor II s, take the next thirty seconds, as the exerts in your field, to instruct your artners. Little rofessor I s, it s your turn to listen to me, Little rofessor II s you know the routine T Slide 18 Homozygous x Homozygous F. x Genotyic ratio: 0 : 4 All offsring will e heterozygous henotyic ratio: 4 lack coat : 0 red coat Little rofessor I s take the next thirty seconds to teach your artners. Little rofessor II s you are ack with me and Little rofessor I s it is your turn to relax. T Slide 19

12 G. x 1. henotyic Ratio a) 3 lack to 1 red or 3:1 2. Genotyic Ratio a) 1: 2: 1 Little rofessor II s, take the next minute to teach your artners this new information. Very good jo! Little rofessor II s take some welldeserved time off, rofessor I's your ack with me. T Slide 20 H. x 1. Genotyic Ratio a) 2: 2 2. henotyic Ratio a) 2 lack to 2 red Little rofessors, take the next thirty seconds to teach your artners this new information. One last time Little rofessor II s lease come ack to me. Little rof s I take the next coule of minutes to relax.

13 T Slide 21. Homozygous x Homozygous. x - All will e red Genotyic Ratio - 4 : 0 henotyic Ratio - 4 red coats : 0 lack coats Take the next thirty seconds to instruct your artners on this information. Once they have finished, distriute the worksheet to each student and allow them three minutes to comlete the unnett squares. Each student is to work out the unnett square and write the genotyic and henotyic ratios next to each square. In your little rofessor airs I would like each of you to look at the information resented in the current overhead. Just like in the ast six examles, is dominant and lack, is recessive and red. In addition I have added a second trait. is dominant for olled and is recessive for horned. You are starting a new SAE, the ull you have ought has a genotye of and you lan to reed him to the heifer you just ought. Her genotye is also heterozygous for oth traits. Take the next five minutes, working with your artner to comlete worksheet three. I also ask you to figure out the genotyic and henotyic ratio for this cross. Good luck,

14 egin. Multile Gene airs: A. Mating 1. = lack & = Red 2. = olled & = horned. ull 1. C. Cow 1. D. What will the henotyic & genotyic ratios e? E. Genotyic Ratio 1. 1 : 2 : 1 : 2 : 4 : 2 : 2 : 1 F. henotye 1. 9 olled and lack 2. 3 olled and red 3. 3 horned and lack 4. 1 horned and red T Slide ractice it! As a fun and different way to let the students ractice working out

15 unnett squares, air students u (according to their aility) and have each student get a iece of sidewalk chalk. Outside on the concrete have the students work out a few rolems using the unnett square. Each student needs to use their own color chalk so that the students can get a searate grade for the ractice. Review & Instruction: Ojectives will e reviewed efore examinations. Exams will e develoed ased on ojectives as taught in class. Instructional Suort: A. References a. Colorado Agriscience Curriculum. Teaching Aids & Equiment: a. Genetics T. Genetics Student T c. Colored encils d. Mendel & Genetics Quiz e. unnett Square Worksheet f. Sidewalk Chalk g. Genetics Test Review h. Genetics Test C. Facilities: a. Agriculture classroom