How Can You Predict Possible Combinations Of Alleles In A Zygote From The Genetic Makeup Of Parents

Biology Lesson: Traits and Inheritance

Biology 501, Summer 2007

Revised Lesson: August 13, 2007

Instructors : Dr. Ingrid Waldron

Jennifer Doherty

TA : Jennifer Tareila

Group Members:

Theresa Lewis-King, Candace Randolph, and Bill Wagenborg

Biology 501

Summer 2007

Revised Lesson: August 13, 2007

Instructors : Dr. Ingrid Waldron

Jennifer Doherty

TA : Jennifer Tareila

Grouping Members: Theresa Lewis-King, Candace Randolph, and Nib Wagenborg

Biological science Lesson: Traits and Inheritance

Lesson Plan Overview:

Human being beings pass particular characteristics from parent to offspring in an orderly process accomplished by ways of their genetic codes, which are independent in the DNA of fertilized egg or sperm cells. Some characteristics will influence a student�southward concrete appearance and others will non. Some children volition resemble their parents considering of these inherited traits. Nevertheless, even if children do not physically look like their parents, they even so have inherited genetic characteristics from their parents.

Unit Objectives:

Students will learn:

How characteristics are passed from parent to offspring.
The deviation between grapheme traits that are expressed (phenotype), and character traits that are not expressed (genotype).
How Biologist utilise a Punnett Square to make prediction well-nigh a person�s genotype

Why teach this Lesson?

Schoolhouse District of Philadelphia

7^th Grade Core Curriculum

Unit of measurement of Study: Prison cell, Heredity, and Classification

Objectives:

Know that every organism has a gear up of genetic instructions that determine its inherited traits
Draw how traits are inherited
Explain how genes and alleles are related to genotype and phenotype
Explain how probability can be used to predict possible genotypes in offspring

Pennsylvania Scientific discipline Standards

PA Standard: Unifying Themes

3.1.7B: Describe the use of models every bit an application of scientific or technological concepts.
3.ane.7C: Place patterns as repeated processes or recurring elements in science and technology.

PA Standard: Enquiry and Design

3.2.7B: Apply process knowledge to brand and translate observations.

PA Standard: Biological Sciences

3.3.7A: Describe the similarities and differences that characterize various living things
3.3.7C : know that every organism has a set of genetic instructions that determine its inherited traits.

(School District of Philadelphia. Science Core Curriculum, 2004)

Background For Teachers

Heredity and Inherited Traits Lesson

Theresa Lewis-King, Candace Randolph, and William Wagenborg

The procedure of instruction involving an organism�due south inherited traits should attempt to brand clearer to students why some children resemble their parents and others practise non. In this lesson, recognizing vocabulary is important, however being able to sympathize the processes and roles involved is the main goal. This information should be used to help students understand:

How traits from their parents are passed to offspring
How some traits make up one's mind their physical advent
How they possess some traits that are not visible.
How genetic traits can be identified and predicted using a Punnett Square

It is also important to recognize that although this data is beingness applied to human beings, it is also true for plants and other animals (Cummings, 2006). Human beings, like all living things, inherit their characteristics from their parents. These traits are passed on through a process that starts with meiosis in each parent and finishes with fertilization of a mother�due south egg from a father�s sperm. The human�s private characteristics and makeup depend on the variation of the gene that he or she receives from each parent. (Cummings, 2006)

Every bit discussed in meiosis , the human gametes , sperm cells in males and egg cells in females, each contain twenty-3 chromosomes. When the sperm and egg cell join in fertilization, a zygote containing forty-six chromosomes, twenty-iii from the mother and twenty-from the father, is produced. These chromosomes incorporate genes that provide the �blueprint� for the developing embryo. The embryo has a pair of genes, one from each parent, which is responsible for specific characteristics. Each gene may contain different alleles, alternative versions of the same gene , for a particular characteristic. For example, an allele for the centre colour gene might code for chocolate-brown eyes, blueish eyes, or hazel eyes. The trait that the infant will have when born is determined by the specific combination of alleles that it received from its parents (Oxford University Press, 2004).

In this lesson, nosotros focus on 2 important classifications of gene alleles that determine a man�due south biological and physical makeup, dominant or recessive . Ascendant alleles code for proteins that perform specific functions in the cell and recessive alleles code for proteins that are either non-performance or have little issue on the cell (Oxford University Printing, 2004). For example, the gene that codes for a protein that produces the pigment melanin that affects pare color on chromosome xi could have two alleles, the allele for the normal product of melanin (skin colour), and the allele for non-production of melanin. The normal producing melanin allele is considered a dominant allele because it codes for a poly peptide to produce the pigment for melanin. The not-melanin producing allele is considered recessive because it codes for a protein that does not produce the pigment for melanin. A dominant allele is expressed in humans when both the paternal and maternal alleles of his/her gene are ascendant or if one of the alleles is the dominant and the other is recessive. If both the mother and begetter� gamete or one of their gametes provide the allele for the normal producing melanin, the child will accept normal skin color. Consequently, the recessive allele is expressed in a human being when both the paternal and maternal alleles are recessive. The female parent and the father�s gametes would both provide the allele for non-producing melanin and thus would issue in albinism (white pare color and hair) in the child Cummings, 2006).

This link provides a list of common ascendant and recessive traits in human being

http://www.blinn.edu/socialscience/LDThomas/Feldman/Handouts/0203hand.htm

(Thomas, 2007).

An organism is homozygous for a trait when they possess two of the same allele, one maternal and i paternal, for a factor . This is truthful when both alleles are either ascendant or recessive. An organism is heterozygous for a trait when they possess a dominant and a recessive allele for the same gene, in which case the dominant trait will be the expressed trait. If an organism is heterozygous, they will withal have 2 copies of a gene, they are carriers of a recessive gene, fifty-fifty though it is not expressed. In this way a parent could pass forth a trait to their child without information technology ever condign apparent. This is important to the agreement of how disorders, such as Sickle Cell Anemia, tin can occur in a child later on it has been carried and passed from previous generations without affecting them. (Oxford University Press, 2004)

Knowing the genetic brand-up of the parents allows us to make prediction near the possible genetic makeup of the offspring. Using a tabular array called a Punnett Square, it is possible to predict the possible character traits of the offspring. In lodge to identify and predict genetic traits, each factor is assigned a letter. If the allele for that gene is ascendant, an uppercase letter is written. If the allele is recessive, then a lower instance letter is written. For example, the melanin producing allele would be labeled �A� because it is dominant and the non-melanin producing allele would be labeled �a� because it is recessive. The grid, adult by R.C.Punnett, is constructed based on the number of all possible combinations of paternal and maternal alleles for item genes. More often than not, a parent only has two alleles for whatsoever i gene. To determine the number of square grids needed to compute the Punnett Foursquare, multiply the number of possible egg genotypes by the number of possible sperm genotypes. For the purposes of this lesson, we are focusing on alleles of ane gene, two alleles from each parent. Thus the filigree volition exist 2 x 2 or four squares. Although it does non have an issue on the outcomes, consistency in the placing of the maternal and paternal alleles on the grid may help students� organization. The paternal alleles for case, are always listed horizontally on the grid, 1 higher up each block and the alleles of the maternal gene are always listed on the filigree vertically, one next to each cake. The paternal and maternal alleles are then put into pairs of two based on their location on the grid (Oxford University Press, 2004) (Friedman, 2004).

Beneath is an example of the apply of A Punnett Square in predicting albinism in children.

Female parent Aa (heterozygous factor-ascendant- normal melanin production- she has normal

peel color, merely is an albinism carrier)

Father Aa (heterozygous gene- dominant – normal melanin product- he has normal

skin color, but is an albinism carrier)

A a

Melanin produced

no melanin produced-albinism

This Punnett Foursquare shows that each child has a 75% take a chance of normal skin colour because three of the four quadrants show that the dominant trait would exist expressed (AA, Aa and Aa ). This Punnett Foursquare also shows that each kid has a 25 % take chances of having albinism because ane of the four quadrants shows that the recessive trait would exist expressed (aa). The Punnett Square can be used for all allele pairs for all genes. Information technology is not meant to be an exact calculation of what the private offspring of these parents volition be, but rather an expression of possibilities because it represents an exact calculation of probability. All of the children built-in to these two parents accept the same probability of inheriting normal skin color and albinism because each pregnancy is an independent occurrence and the probability remains the same. This illustrates a very important concept that is a central to agreement heredity: at that place are traits that may appear in a child that do not appear in either of his/he parents or his/her siblings. (Friedman, 2004)

The genetic makeup of a human is the genotype based on the alleles that he/she obtains from his/her parents. The phenotype is the expression of the genotype modulated by the environment (Oxford Academy Press, 2004). The genotype is an organism�s genetic make upward. Specifically, it is the complete set of genetic data in every body cell of the organism. This genetic representation is inscribed in every human�southward DNA and is replicated throughout the torso. It is the listing of possible alleles for genes inherited from the female parent and father that allow u.s. to use a Punnett Foursquare to predict the possible genetic makeup of the offspring. The phenotype is the observable characteristics of whatsoever organism that are adamant by its genotype combination of alleles. These traits determine a homo�s physical appearance, pilus color, middle color, pinnacle, skin tone, etc. Along with genotype, the interaction a human has with the environment tin can play a crucial role in determining a person�south phenotype. Factors such as diet, geography, (surroundings and climate) and physical activities can change or change someone�southward phenotype. For instance, Phenylketonuria (PKU) is a recessive disorder associated with the bodies� inability to metabolize an essential amino acid, phenylalanine. In Infants who are homozygous for PKU, phenylalanine builds up to toxic levels in their cells and causes severe mental retardation and other developmental problems. If the baby is given a restricted diet low in phenylalanine and maintain this nutrition throughout life, then the toxic affects of phenylalanine is reduced in the prison cell and some developmental delays tin be avoided. This shows how the environment tin can bear upon a human�s phenotype (Snustad, 1997).

The Human Genome Project, completed in 2003 funded by the U.S. Department of Free energy and the National Institutes of Health, is a way for the science earth to examine human DNA and identify the estimated 30,000 genes that are present. This research will be used for a variety of reasons that include: understanding the different functions of Dna, shedding light on dissimilar genetic diseases and providing more of a basis for homo identification through Deoxyribonucleic acid samples that can used in such things as criminal cases. The project itself is finished, simply the assay of data will continue for some fourth dimension. As more is learned from the data, a better sense of human genotype will be developed. (HGMIS, 2006)

Although we may understand a lot about homo traits and inheritance, at that place is still more to be discovered. Students need to exist enlightened that learning about heredity, like all of things in scientific discipline, is an ongoing process. Many of their questions may be answered, but many more may arise.

Grade Level 7 Science: Traits and Inheritance

Approximate Class Time : Five Form Periods (45 minute periods)

Big Idea : Why do some children resemble their parents more than others?

Lesson Construction:

The School District of Philadelphia uses the Benchmarks for Science Literacy developed by the American Clan for the Advocacy of Scientific discipline (AAAS) and the National Science Education Standards developed by the National Inquiry Quango to provide teachers a framework for science instructions. The overall goal is to provide students with an opportunity to fully appoint in the learning process by request questions, making predictions, conducting experiments and investigations, analyzing data, using technology, communicating using acceptable scientific language.

This lesson volition follow the Scientific discipline of Philadelphia K-viii Instructional Model. (The School Commune of Philadelphia, 2004):

� Engage

� Explore

� Explain

� Extend

� Evaluate

Student Background Knowledge

Students should be familiar with how a scientists conducts an investigations; including request questions, posing hypothesis, designing experiments, collecting and analyzing data, and communicating results.
Students should accept a basic understanding of the part and structure of cells in the human trunk, including the central part that Deoxyribonucleic acid plays in giving instructions to the cell.
Students should sympathise how cells divide through the process of mitosis . They should besides know how sperm and egg cells (gametes) are kformed through the process of meiosis .

Lesson#1:

Misconceptions: Students may think that if they look more than like one parent, then they have more than of that parent�s genes. Students sometimes believe that they have inherited traits from only 1 parent or the other. (Holt, et. al, 2005) It is important that the teacher is enlightened of what students already know considering research on how students acquire stress the importance of identifying the concepts that students bring with them into the classroom. When confronted with new information, it is believed that students volition either; ane.) Totally delete prior knowledge in favor of new information, 2.) Modify or change the prior knowledge so it is in line with the new information, 3.) Alter or change the new data and then it is in line with the prior noesis, 4.) Totally decline the new data. (Sewell, 2002)

Appoint: During this part of the lesson, the instructor should heighten questions that volition hopefully get students interested in the topic of report. This part of the lesson will also give the teacher an idea of what students already know, and likewise insight into misconceptions that might interfere with students learning new concepts.

Warm-upward Activity

Teacher : Tape responses on nautical chart paper and put the student�s name abreast their idea. Look for possible themes that can be grouped together, this will indicated general areas of misconceptions. At the end of the unit, information technology is important to revisit these responses with students to decide if and how any of their original ideas have changed.

Instructor asks:

What determines how you look, i.e. your hair colour, pare color, eye colour?
Why do the aforementioned parents (same mother and father) have children that look different?
Why exercise some children look only like one parent or the other? Why do some children await like both parents? Why practise some children await like neither parent?

Group Activity: Wearable Combos

Label 3 bags: hats, scarves, and gloves (these represent 3 genes for specific character traits that children tin inherit from parents ).
Put 5 different hats, scarves, and gloves in their corresponding pocketbook, for instance; red, green, blue, yellow, orangish (these stand for the dissimilar alleles, alternative versions, for the genes for specific grapheme traits children inherit from parents )
Without looking take students select 1 particular from each bag, do this in groups of five and render items to the bag after each child records their pick .
Students record their outfit.

Teacher : Make a Course Chart, record educatee combinations

Wrap-upward questions:

Were any ii outfits the same?
Did we see all possible combinations?
Even with the same available choices (same parents ), why did y'all we get such variation in outfits?

Journal Reflections : (children tin share reflections if time permits)

Accept students explain how they call up the procedure of selecting dissimilar objects from the pocketbook without looking might be like parents passing traits to their children.
Why was it important to render the items to the bag after each student selected?

Lesson #2 : Teacher Directed Lesson

Explicate : This function of the lesson is a formal introduction of key concepts and vocabulary that students will need to understand and achieve the learning outcomes stated in the lesson objectives. Students should have an opportunity to enquire questions for description, explain concepts in their own words, and do additional enquiry.

Teacher: Whole-Group Lesson

Yous have already learned that through the process of meiosis, human gametes, sperm cells in males and egg cells in females are formed. Each gamete, egg and sperm cell, contains twenty-three chromosomes.
When sperm and egg cells bring together in fertilization, a zygote containing forty-six chromosomes, xx-three from the mother and twenty-three from the father, is produced. These chromosomes contain the information (genes) that provides the �blueprint� for the developing embryo.
Each gene may incorporate different alleles, alternative versions of the aforementioned factor , for a item characteristic. For case, an allele for the middle color cistron might lawmaking for brown eyes, blue eyes, or hazel optics.
The genetic makeup of a human is determined past the specific combination of alleles that it received from its parents, one from the mother, and one from the begetter.
The genetic makeup of a human is the genotype based on the alleles that he/she obtains from his/her parents. The genotype is the complete ready of genetic information in every torso prison cell of the organism. This genetic representation is inscribed in every human�s Dna and is replicated throughout the trunk.
The phenotype is the expression of the genotype. The phenotype is the observable characteristics of any organism that are determined by its genotype combination of alleles. These traits determine a human�southward physical appearance, pilus color, centre colour, peak, peel tone, etc.
A Dominant gene describes the allele that is expressed in the phenotype when two different alleles of a gene are nowadays in the cells of an organism. This will determine what an individual volition look similar.
A Recessive factor describes the allele that is non expressed in the phenotype when two unlike alleles are present in the cells of an organism. Although these characteristics are non expressed, the individual yet carries these traits.

Unit of measurement Vocabulary:

Teacher: Introduce and talk over key vocabulary terms, give students examples where appropriate and allow times for students to add words to science journal.

* Student should create and maintain a science journal that contains key vocabulary and concepts in words, pictures, diagrams, and formulas.

Inheritance : the transmission of particular characteristics from generation to generation past means of the genetic code, which is transferred to offspring.
Traits : Any detectable phenotypic property of an organism, a character.
Phenotype : The observable characteristics of an organism.
Genotype : The genetic composition of an organism, the combination of alleles it posses.
Cistron : A unit of measurement of heredity composed of Dna. A gene is visualized as a discrete particle, forming part of a chromosome that determines a particular characteristic. A gene occupies a specific position on a chromosome. In molecular genetics, it may exist divers as the sequence of nucleotides of DNA and RNA concerned with a specific function.
Allele : One of the alternative forms of a gene. In a diploid cell in that location are ordinarily 2 alleles (i from each parent), which occupy the same relative position on homologous chromosomes. Within a population there may be numerous alleles of a cistron, each has a unique nucleotide sequence.
Ascendant : (in genetics) Describes the allele that is expressed in the phenotype when 2 different alleles of a gene are nowadays in the cells of an organism.
Recessive : The allele that is not expressed in the phenotype when 2 different alleles are present in the cells of an organism.
Homozygous: Describing an organism or cell in which the alleles at a given locus on homologous chromosomes are identical (they may exist either dominant or recessive).
Heterozygous: Describing an organism or cell in which the alleles at a given locus on homologous chromosomes are different.

Wrap up: Homework Assignment:

Assign Reading: (School District of Philadelphia Core Curriculum recommendations)

You lot and Your Genes , National Geographic Reading Trek
Uncovering the Structure of Dna , National Geographic Reading Expedition

Lesson #3 and #4: Hands-on Lab Traits and Inheritance

Engage:

Teacher states : Many times children and adults wonder why they practice or do non resemble their parents. As you lot take learned, you inherit genes from your parents that make up one's mind specific characteristics such as their complexion, pilus texture, and the structure of your nose, center color, and many more numerous characteristics.

Where are your genes located in your body?

Educatee should brand the connexion that genes are office of DNA molecules and DNA molecules are contained in the chromosomes located in the nucleus of the cell.

How does a child inherit genes from his or her female parent and father?

Students should be able to explain the process of meiosis, how a child gets 20-three chromosomes from the mother and twenty-three chromosomes from the begetter.

In today�s lab, we will consider a very mutual characteristic in people, cheek dimples.

Explore: Allow students to work together in groups to generate and test ideas that they may accept concerning the topic of study.

Explain : Students should be able to �testify� what they know. This is the part of the lesson that gives students an opportunity to practice a hands on lab designed to increment their understanding of primal concepts.

Activity Ane:

Cheek Dimples are a very common characteristic in people. 1 allele for the gene that codes for cheek dimples is given the symbol �D� . The other allele that codes for no dimples is given the symbol � d� . A person that has cheek dimples will take a genotype of either DD ( homozygous ) or Dd ( heterozygous ). Both of these combinations of alleles will result in a kid with dimples.

Why will both of these combinations produce a child with dimples?

A person without cheek dimples volition accept a genotype for dd (homozygous ).

Why will this combination result in a kid that has no dimples?

Biologists use a Punnett Foursquare to help bear witness the possible genetic combinations of zygotes. The alleles for each parent must exist crossed with the other. For the purposes of this lesson, we are focusing on alleles of one gene, two alleles from each parent. Thus the grid volition be 2 x 2 or four squares. The paternal alleles are listed horizontally on the grid, one above each block and the alleles of the maternal factor are listed on the grid vertically, one adjacent to each block. The paternal and maternal alleles are then put into pairs of two based on their location on the filigree (Oxford Academy Press, 2004) (Friedman, 2004).

Complete the Punnett Square below for both parents who have the genotype DD (homozygous).

Father (sperm)

Mother (egg)

Each square that you lot crossed represents a possible offspring�s genotype.

How many have the genotype�

DD _____

Dd _____

dd _____

What fraction of them is? DD _____, Dd ________, dd _________

How many of these offspring will have dimples? Why?

Given the parent�southward genotype, will any of the offspring take no dimples? Why?

In the to a higher place example, both parents accept the same allele for the gene that codes for cheek dimples, however there are other combination of factor alleles that parents tin can possess.

What are some other possible combinations that ii parents could have?

Allow examine some other possible parent combination.

Consummate the Punnett Square below for both parents who have the genotype Dd (heterozygous)

Father (sperm)

Female parent (egg)

Each foursquare that you crossed represents a possible offspring�southward genotype.

How many take the genotype��

DD _____

Dd _____

dd _____

What fraction of them is? DD _____, Dd ________, dd _________

How many of these offspring volition have dimples? ______.

What are their genotypes? ________, _________.

How many of these offspring volition non take dimples? ______.

What are their genotypes? _________.

Given the parent�s genotype, volition any of the offspring have no dimples? Why?

Extend: Allow students to employ what they have simply learned. They can use this information to an example that they make themselves.

Complete the Punnett Square below for a parent with another combination of alleles.

Begetter (sperm)

Female parent (egg)

Each square that you crossed represents a possible offspring�due south genotype.

How many have the genotype��

DD _____

Dd _____

dd _____

What fraction of them is? DD _____, Dd ________, dd _________

How many of these offspring will have dimples? ______.

What are their genotypes? ________, _________.

How many of these offspring will non have dimples? ______.

What are their genotypes? _________.

Write the phenotypes (volition the child accept dimples or no dimples?) for each set up of alleles, and describe a picture to represent it.

DD Dd dd

_______________ _______________ _______________

Explicate how two individuals with the same phenotype can have dissimilar genotypes?

Activity Ii:

Genotype Probability

Because children receive half of their genetic makeup from each parent, biologist can use their agreement of probability to predict the possible outcomes of a child�southward genotype and therefore their phenotype . However, random variation in which sperm will fertilize which egg may produce very dissimilar results from the predicted upshot.

What can be done to command for random variation?

The Punnett Square beneath illustrates the possible combinations of genotypes when both parents are heterozygous for cheek dimples, �Dd�.

Begetter (sperm)

Female parent (egg)

What fraction of this couple�southward children will take a genotype of �DD�? __________

What fraction of this couple�s children volition have a genotype of �Dd�? __________

What fraction of this couple�southward children will have a genotype of �dd�? __________

The fraction of unlike genotypes tin can exist expressed in the ratio, 1:2:1.

What is the probability (change the fractions to percents) of the post-obit outcomes?

DD ________

Dd _________

dd ________

Explore: Let students to work together in groups to generate and test ideas that they may have apropos the topic of written report.

In this activity, we will use a two-side coin to help simulate the random assortment of gene alleles. There is a 50-50 adventure that egg or sperm cell volition take the �D� or �d� allele.

Split the course into �fathers� and �mothers�
Give each student a 2-side coin or chip. The heads will represent the dominant allele D� for cheeks dimples and the tail will represent the recessive allele for no cheek dimples �d�.
Students should find someone to a mate. (You may have to assign partners if necessary)
Each pair of student will produce four offspring past tossing their money and recording the genotype and phenotype of their zygote. (toss the money four unlike times.
How many zygotes with genotype �DD�, �Dd�, and �dd� were produced? What were the phenotypes of these offspring?
Did your results friction match the prediction from the Punnett Square?
What tin be washed to get results that are closer to the predicted result? (Students should suggest repeating this activity more times or getting a larger sample)
Permit students to echo this activity again, this time making four different sets of four offspring. Tape information in the following chart.

	DD	Dd	dd
First four offspring
Second iv offspring
Tertiary four offspring
Quaternary four offspring
Full
	/16	/xvi	/sixteen
Predicted fractions from Punnett Square

Are you fractions closer to the predicted outcome on the Punnett Foursquare? (Teacher could combine group data to make the class chart, does this ameliorate the probability of matching predicted event?)

Wrap-upward Easily-on Lab

� Students complete action sheets and discuss their results in-grouping.

Teacher-directed discussion will makes connections to reinforce the cardinal concepts.
Review Lab sheets with students

Lesson adapted from : North Key Regional Technology in Didactics Consortium.

Genetics, Dr. Scott Poethig, Dr. Ingrid Waldron, and Jennifer Doherty, Section of Biology, University of Pennsylvania.

Lesson #5

Evaluate: Evaluation of pupil learning is an ongoing procedure during these lessons. The teacher will have numerous opportunities to listen and observe students every bit they talk and interact with each other. In that location volition also be formal assessment that will provide feedback for the students to heal them monitor their ain learning.

Formal Assessment :

Instructor checks/grades activity sheets, gives students direct feedback

Extension Question : If a homozygous dimple (DD) crosses with a heterozygous dimpled (Dd) and they accept 8 children, what is the probability an offspring will be heterozygous dimpled (Dd)? Draw a Punnett Squares and show calculations below.
Personal Analysis: Using the terms ascendant, recessive, alleles, homozygous and heterozygous explain why you may or may not resemble your parents.

References

A Lexicon of Biology. Oxford Academy Press, 2004. Oxford Reference

Online. Oxford University Press. Academy of Pennsylvania. 7 July 2007 http://www.oxfordreference.com/views/ENTRY.html?subview=Main&entry=t6.e147

Confrey, Jere. A Review of the Research on Student Conceptions in Mathematics, Scientific discipline, and Programming, past Review of Research in Didactics � 1990 American Educational Inquiry Association

Cummings. Michael R. (2006) Transmission of genes from generation to generation. Human heredity: Principles and issues (seventh edition)

Commonwealth of australia:Thomson/Brooks/Cole.

Felix de la Cruz, "Phenylketonuria", in AccessScience@McGraw-Hill, http://proxy.library.upenn.edu:2805, DOI 10.1036/1097-8542.506900, last modified: July 12, 2002.

Friedman, Thomas B., Drayna, Dennis �Mendelian Genetics" Encyclopedia of

Evolution . Ed. Mark Pagel. Oxford University Press 2003.

Academy of Pennsylvania. 11 July 2007 <http://www.oxfordreference.com/views/ENTRY.html?subview=Master&entry=t169.e267>

Holt, Rinehart and Winston, 2005. Cells, Heredity, and Classification. Holt, Rinehart and Winston. Austin. TX.

Human Genome Management Data Organization (HGMIS) (2006)

Human being genome projection data.

Retrieved July fourteen, 2007 from

world wide web.ornl.gov/sci/techresources/Human_Genome/home.shtml.

M. Suzanne Donovan and John D. Bransford, Editors 2007. How Students Learn

History, Mathematics, And Scientific discipline In The Classroom. National Inquiry Quango

the National Academies. The National Academies Printing. Washington, D.C.

North Central Regional Engineering science in Education Consortium 2005. http://www.ncrtec.org/tl/camp/gene/gene6.htm

Poethig, Scott, Waldron, Ingrid, and Doherty, Jennifer. 2006. Genetics. Department of Biology, University of Pennsylvania.

School District of Philadelphia. Core Curriculum, 2004. Songhai Press, Philadelphia, PA.

Sewell, Audrey. Constructivism and Student Misconceptions, Why Every Instructor Needs to Know About Them. Australian Science Teachers� Periodical, v48 n4, p.24-28. December. 2002.
Snustad, D., Peter, Simmons, Michael J., Jenkins, John B. (1997)

Extensions of mendelism Principles of genetics. New York: John Wiley& Sons

Thomas, Larry D. Dominant and recessive traits. Blinn College Psychology Professor Retrieved July 7, 2007 http://www.blinn.edu/socialscience/LDThomas/Feldman/Handouts/0203hand.htm

Source: https://www.sas.upenn.edu/~them/Biology501lesson.htm

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