MENDELIAN GENETICS
http://www.brainpop.com/science/cellularlifeandgenetics/genetics/
http://www.brainpop.com/health/geneticsgrowthanddevelopment/heredity/
http://www.brainpop.com/health/geneticsgrowthanddevelopment/geneticmutations/

GENETICS VOCAB: genetics, Gregor Mendel, genotype, phenotype, gene, allele, dominant, recessive, chromosome, punnett square, monohybrid cross, dihybrid cross, genome, paternal, maternal, heredity, complete dominance, incomplete dominance, codominance, homozygous, heterozygous, pedigree, P generation, F1 generation, F2 generation, deletion, mutation, disjunction, hybrid, purebred.


mendel.gifGregor Mendel, was a monk in Austria in the mid-1800s who raised peas in the monastery gardens. While breeding his peas, he made some big discoveries. They were discoveries about genetics.
The peas had several traits he could see. Some plants were tall and some were short. Some had wrinkled pods and some had smooth pods. Some pods were green and some where yellow. The flowers were white or purple. Mendel looked at each trait and learned how they were passed down to the offspring plants. Since plants breed using pea_traits2.jpgpollen, Mendel controlled which plants pollinated other plants. This was how he discovered many important genetic rules.

How an individual looks and what their genetic code is sometimes do not match up. This is the difference between genotype and phenotype. The genotype is the actual genetic make up of an individual. The phenotype is what that individual looks like.

Traits that show up more often are called dominant traits. Traits that show up less often are called recessive traits. If an individual with dominant traits breeds with an individual with recessive traits, this can result in a hybrid offspring. Hybrid individuals can look like they have dominant traits (phenotype), but actually be hybrid (genotype).
Hybrid plants are different from dominant plants even if they looked the same. Each gene has two chances at a trait – two copies — two alleles. So a hybrid plant could be carrying the allele for a recessive trait even if you can’t see it. So, for example, a hybrid plant might be tall like its dominant parent, but it still could have an allele for shortness that you don’t see. This is the difference between genotype and phenotype. The genotype is the actual genetic make up of an individual. The phenotype is what that individual looks like.

This can be illustrated with a simple chart. It’s called a Punnett’s Square.

jpeg-Punnett_square_mendel_flowers_svg.JPG
Let's look at a MONOHYBRID CROSS of two heterozygous parent plants for the trait of flower color (purple & white). Observe the Punnett square, Answer the questions below using the Punnett.

1) What type of dominance is exhibited by pea flower color genes?
2) Which color is the dominant allele?
3) What letter represents the dominant allele?
4) Which color is the recessive allele?
5) What letter represents the recessive allele?
6) What would a heterozygous pea flower look like if this trait was governed by the rule of CODOMINANCE?
7) What is the expected PHENOTYPIC frequency of flowers the offspring? (%white & %purple)
8)What is the expected GENOTYPIC frequency of the offspring? (%homozygous dominant,%homozygous recessive, %heterozygous)
9)What would be the expected PHENOTYPIC outcome if one of the parent plants was homozygous dominant and the other heterozygous? Draw a punnett square to support your claim.
10) What would be the genotypic and phenotypic outcome if you had a monohybrid cross of two homozygous recessive pea plants? Draw a punnett square to support your claim.

Look at the example of the monohybrid cross of the red & white flowers below and answer the following questions.

external image incomplete%20dominance.jpg
11) What is the phenotype of the rr flower?
12) What is the gentoype of the red flower?
13) Look at the F1 (1st Filial) offspring of the P(parents) plants and decide: what type of dominance governs flower color alleles for this flower species? Explain how you know this.
14) Why would crossing a pink flower with a white flower NEVER produce a red offspring?

MORE PRACTICE
http://biology.clc.uc.edu/Courses/Bio105/geneprob.htm
http://ww2.unime.it/weblab/mirror/ExplrSci/dswmedia/mouse.htm













MULTIPLE ALLELE AND VARYING DOMINANCE: HUMAN ABO BLOOD TYPING

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CHECK YOURSELF:
Using Punnett squares and the dominance rules for blood type, show all possible genotypes for children whose parents' phenotypes are Type A and Type AB. For each punnett give the phenotypic expected frequencies and the genotypic expected frequencies.
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WHO KILLED SHAMIRI DAVIS?


BLOOD TYPE LAB RESULTS
case 8675309, West Palm Beach, Florida.............Chief Forensic InvestiGATOR, A.R. Buffone
University of Florida Crime Lab........Gainesville Florida

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SHAMIRA DAVIS RESULTS






DALEESHA JONES RESULTS






HARVEY WILLIS RESULTS






MIKE REED RESULTS




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STEVE O'HARE






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BLOOD EVIDENCE COLLECTED FROM SHOWER




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Who is ruled out and who would you take to the DNA testing lab for further comparison?



PRACTICE QUESTIONS: ALIEN GENETICS
Trait
Dominant Phenotype
Recessive Phenotype
Body color
(Y) Yellow
(y) Orange
Number of Antennae
(A) 2
(a) 1
Eye color
(P) Purple
(p) White
Eyesight
(E) Glasses needed
(e) Glasses not worn
Number of Body Rings
(R) 3
(r) 5
alien15mp.gif

1. A heterozygous male mates with a pure yellow female. What is the chance this couple will produce an orange baby? Do so by showing the Punnett square.

2. Two purple-eyed aliens mate. Both aliens are hybrid for the eye color trait. What is the chance this couple will produce a baby with a homozygous recessive genotype? Use a Punnett Square and list the probability.

3. A heterozygous female with 3 body rings mates with a 5-ringed male. What is the chance that this couple will have a baby that looks like its mother? Use a Punnett Square and list the probability.

4. A purebred male alien displaying the dominant body color mates with a female that is homozygous recessive for this characteristic. What is the chance that this couple will have a baby with a hybrid genotype? Use a Punnett Square and list the probability.

5. A male alien with 1 antenna mates with a female alien who has 2 antennae. The female is heterozygous for the antenna trait. What is the chance that this couple will produce a baby with the recessive phenotype? Use a Punnett Square and list the probability.

6. An alien couple, both of which wear glasses, are having a baby. The male's genotype is heterozygous. The female is phenotypically dominant but does carry the recessive allele. What is the chance that this couple's baby will have to wear glasses? Use a Punnett Square and list the probability.

7. A 3-ringed female mates with a homozygous male. The female has been genetically tested and is carrying both the dominant and the recessive allele for this trait (she is heterozygous). The male displays the recessive phenotype. What is the chance that this couple will have a genetically pure (homozygous) baby? Use a Punnett Square and list the probability.

8. I have a yellow alien...but I want to know if it is has the homozygous dominant genotype (YY) or the heterozygous genotype (Yy).
a)What can I do to check it besides take its DNA and analyze it?
b)If it is homozygous, what would be true of 100% off its offspring? Prove it with a Punnett Square.
c)If it ever had an orange offspring, what would have to be true about its genotype?

9. Draw and color an alien with this genotype: YyAaPpEeRr

10. Draw and color an alien with this genotype: yyaappeerr

11. P-cross
a)Show a P(Parent) cross between two aliens purebred for the 2 eye colors on a punnett square.
b) What is the phenotypic expected frequency off offspring IF this trait is goverend by complete dominance?
c) What if it was governed by incomplete dominance? (Use P and P')
d) What if it was governed by codominance? (Use P and P')
e) What do we call this first generation of offspring of the P cross?

12. Show an F1 x F1 cross and give the phenotypic frequency of the offspring if this trait of eye color is governed by codominance.


http://pbskids.org/dragonflytv/games/game_dogbreeding.html




Fruit Fly Genetics Lab



Genetics Games
http://www.nature.ca/genome/04/041/041_e.cfm