Genetics What is an ALLELe? Different form/version of a gene You inherited ONE ALLELE from each parent for each trait. For example – Gene = eye color.
Post on 18-Dec-2015
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GeneticsGenetics
What is an ALLELe?What is an ALLELe?• Different form/version of
a gene• You inherited ONE
ALLELE from each parent for each trait.
• For example – •Gene = eye color•Allele = blue, hazel, brown, and green
Dominant vs. Recessive AllelesDominant vs. Recessive Alleles• Dominant allele hides the
recessive allele.– The Dominant allele always
shows/is visible– For example – hair color –
brown is dominant to all other hair colors
– EX: mom gave you the allele (gene) for brown hair. Dad gave you the allele for blonde hair.You will have what color hair?
– Answer: Brown hair
Dominant vs. Recessive Alleles Dominant vs. Recessive Alleles (Cont.)(Cont.)
• Recessive allele is always hidden if a dominant allele is present.
• You must inherit 2 recessive alleles for the trait to show up/become visible.– EX:– hair color – blonde is
recessive to all other hair colors
– mom has to give you the allele (gene) for blonde hair and dad gave you the allele for blonde hair, you will have blonde hair!
Writing Alleles?Writing Alleles?
• All alleles are assigned letters
• Dominant allele=CAPITAL letters– B=(Brown eyes)
• Recessive allele – lower case– b= (blonde eyes)
• Two letters pair for each trait – one passed on from mom and one from dad
• Using the letter B tell me what a person with brown hair would look like– BB_____– Bb_____– bb_____
• Is this trait dominant or recessive?– DOMINANT
• What if the person had blonde hair (recessive trait)?– bb
How you get your traits?How you get your traits?
•Dimples are a dominant trait. Non dimples are recessive. If both parents have have dimples would all the kids have dimples?
Genotype vs. PhenotypeGenotype vs. Phenotype•Phenotype-
physical trait– can be seen– Brown or blonde
•Genotype- genetic makeup– Alleles inherited– (not seen BB, Bb)
Genotype/Phenotype PracticeGenotype/Phenotype Practice• Are the following
genotype or phenotype
• Hazel Eyes. – Phenotype
• BB – Genotype
• Long Toes – Phenotype
• Rr– genotype
• Tt– genotype
• Ear Hair– Phenotype
• Ff– genotype
• Freckles– phenotype
Homozygous vs HeterozygousHomozygous vs Heterozygous
• PREFIXES:
– HOMO=SAME alleles for a specific trait ( TT or tt)
– HETERO=DIFFERENT alleles for a specific trait (Tt or Bb)
Practice-Practice-• 1.) If you inherited the 2 alleles for blue
eyes (1 from each parent), your phenotype is __________, your genotype is _____, and you’re _____ zygous.
• 2.) If you inherit the dominant allele for dimples from your dad, and the recessive for no dimples from your mom, your phenotype is ______, your genotype is _______, and you’re ____ zygous.
Practice ProblemsPractice ProblemsWill the following plants be tall or
short? T=tall and t=shortTtTTttAre the following plants homozygous or
heterozygous?TTTttt
PracticePractice
What is the phenotype of the following plants?
TtTTtt
• Genotype codes for Phenotype.• P = Purple and p= white• Y = Yellow and y = green• R = Round and r = wrinkled• Genotype is RR, the Phenotype is ______.• Genotype is YY, the Phenotype is ______.• Genotype is pp, the Phenotype is ______.• Genotype is Rr, the phenotype is ______.• Genotype is Yy, the phenotype is ______.• Phenotype is wrinkled, the genotype is ____.• Phenotype is green, the genotype is _____.
• Genotype codes for Phenotype.• P = Purple and p= white• Y = Yellow and y = green• R = Round and r = wrinkled• Genotype is RR, the Phenotype is ______.• Genotype is YY, the Phenotype is ______.• Genotype is pp, the Phenotype is ______.• Genotype is Rr, the phenotype is ______.• Genotype is Yy, the phenotype is ______.• Phenotype is wrinkled, the genotype is ____.• Phenotype is green, the genotype is _____.
• . Write dom. For dominant or rec. for recessive next the letter.•
A ______• C ______• d _______• e _______• F _______• f ______• v ______• P ______• m ______• M ______• Q _______• n ________• b ________• X ________• Y _________•
• . Write Ho. for homozygous or He. for heterozygous.••
AA _____• Bb ____• Cc ____• DD _____• eE _____• Ff ____• Gg ____• Hh ____• Kk ____• Mm ____• Nn ____• RR ____• Ss ____• NN ____•
• . Write Ho. Dom if it is homozygous dominant, Ho. Rec. if it is homozygous recessive or He if it is Heterozygous.
• AA ____• BB ____• Cc ____• dd ____• FF ____• qq ____• SS ____• TT ____• VV ____• Tt ____• uu ____• WW ____• ii ______• xx ____• bb ____•
Law of SegregationLaw of Segregation•What is segregation
– separation of alleles•When does this occur?
–During meiosis (formation of sex cells)•Why do they segregate?
–So each gamete only carries a single copy of each gene.
Law of Independent Law of Independent AssortmentAssortment• What is independent assortment?
– Genes/alleles separate independently during meiosis.
– Genes don’t influence inheritance of other genes•(Inheriting blue eyes doesn’t mean you’ll automatically inherit blonde hair)
•Seed color does not influence seed shape
• Dihybrid Crosses (2 trait punnet square) demonstrates this law.
More on genetics….to be More on genetics….to be continued.continued.
Hot Celebrities’ allelesHot Celebrities’ alleles
• Think of the hottest looking male/female celebrities you can think of.
• Write their names. Next to their names list the 3 alleles they have that make them so attractive.
• Be prepared to share your PG-13 rated alleles
Mom &/or Dad got it But you don’tMom &/or Dad got it But you don’t
• Picture what your parents look like
• List some traits one or both parents have but you don’t. For ex: eye color, hair color, attached ear lobes, dimples, tall, short, etc.
• You may have inherited some traits but they’re hidden. Here is why………
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