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91. Cell Reproduction Notebook Check 92. Karyotype Lab (graded) 93. Intro to Genetics Reading Guide (stamped) 94. Genetics Notes 95. Punnett Squares 96. More Punnett Square Practice 97. Exceptions to Mendel’s Rules 98. Oompah Loompa’s 99. Progress Report #6 100. POP QUIZ! - PowerPoint PPT Presentation
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•91. Cell Reproduction Notebook Check•92. Karyotype Lab (graded)•93. Intro to Genetics Reading Guide (stamped)•94. Genetics Notes•95. Punnett Squares•96. More Punnett Square Practice•97. Exceptions to Mendel’s Rules•98. Oompah Loompa’s•99. Progress Report #6•100. POP QUIZ!•101. Pedigrees (a & b)•102. Ugly Baby Lab•103. Genetic Disorders
• Finish Genetic Disorders #103• 3/29 & 3/30 Genetics Unit
TEST!
HOMEWORK!!
a medical procedure used to diagnose chromosomal disorders in a developing fetus. A small amount of amniotic fluid, which contains fetal
tissues, is extracted from the amniotic sac surrounding a
developing fetus, and the DNA is examined.
AMNIOCENTESIS
GENETICS #94• Gregor Mendel = father of heredity–Mid 1800s–Studied garden pea plants (because they
could produce purebred individuals)–Studied how traits were passed from one
generation to the next
–Mendel came up with several important concepts
1. Parents pass on genes2. For each trait, an organism has 2 genes (1
allele from Mom and 1 from Dad)3. Alleles can be dominant and recessive• Tall plants could equal TT or Tt, short = tt•Genotype = genetic make-up for trait (TT)• Phenotype = physical look of trait (tall)
Law of Dominance• If organisms contain two identical
alleles for a trait, it shows that trait.Curly hair = HHStraight hair = hh
• If organisms contain two different alleles for a trait, it shows the dominant trait.Curly hair = Hh
HOMOZYGOUS ALLELES
HETEROZYGOUS ALLELES
Punnett SquaresUsed to
predict the possible
combinations of dominant
and recessive alleles in the
offspring.Genotypic ratio = 1 RR : 2 Rr : 1 rrPhenotypic ratio = 3 pink : 1 yellow
• Dad = XY, some sperm have X, some have Y• Mom = XX, all eggs
have X because that’s all Mom has to donate• Who determines
gender of baby – Mom or Dad?
Determining Gender!
Law of Independent Assortment
The genes for traits found on different chromosomes separate independently
when gametes are made.
Test CrossA deliberate
genetic cross with a homozygous
recessive individual that can be used to
determine whether an organism is
homozygous or heterozygous dominant for a
trait.
?
Phenotype is a mix of geneticsand environment
MostlyEnvironment Mix
MostlyGenetic
Language Height Blood typeReligion Weight Eye color
Intelligence
Nature vs. Nurture Debate
1. Green pea plant (GG) X Green pea plant (Gg)2. Tall plant (TT) X short plant (tt)3. Two tall plants (Tt)4. Two white flowers (white = recessive)5. Homozygous red flower X white flower6. Homozygous dominant brown mouse X
heterozygous brown mouse (tan = recessive)7. Heterozygous white rabbit X black rabbit.8. Two heterozygous white rabbits. (black = rec)9. How would you figure out if a purple plant
(dominant) is heterozygous vs. homozygous?
#96 More Punnett Square Practice(make Punnett Squares & describe offspring using genotypic and phenotypic ratios)
GENOTYPIC RATIO
PHENOTYPIC RATIO
Sometimes genetics isn’t always as simple as Mendel’s
Law of Dominance
Exceptions to Mendel’s Rules
#97
• Heterozygote is a BLEND of the 2 homozygotes• RR = red flowers• rr = white flowers• Rr = PINK flowers• Cross two pink flowers.• Genotypic ratio 1:2:1• Phenotypic ratio
Incomplete Dominance
1 red: 2 pink: 1 white
Codominance• Heterozygote show BOTH traits• BB = black cows• WW = white cows• BW = black & white• BB X WW• All BW offspring• Genotypic ratio = 0:4:0• Phenotypic ratio = 0:4:0
Multiple Alleles• Traits that have more than two alleles.• Blood types –
3 allelesA and B are co-dominantO is recessive to A and B
4 phenotypes1)Type A
blood contains “A” proteinsgenotype: AA or AO
2) Type Bblood contains “B” proteins (genotype: BB or BO)
3)Type ABblood contains both proteins genotype: AB
4) Type Oneither protein present in bloodGenotype: OO
• AB is an example of ________________.
Polygenic Inheritance• Several genes are inherited
from each parent for 1 trait.• Many possible phenotypes.• Examples: skin color, eye color,
height, weightABC, ABc, AbC, aBC = dark
abc, abC, Abc, aBc = light
ABC ABc AbC Abc aBC aBc abC abc
ABC 66 5 5 4 5 4 4 3ABc 5 4 4 3 4 3 3 2AbC 5 4 4 3 4 3 3 2Abc 4 3 3 2 3 2 2 1aBC 5 4 4 3 4 3 3 2aBc 4 3 3 2 3 2 2 1abC 4 3 3 2 3 2 2 1abc 3 2 2 1 2 1 1 0
• Located on X chromosome• Females are only carriers• Mostly males are affected• Colorblindness, hemophilia, baldness• XBXB = normal female• XBXb = carrier female• XbXb = colorblind female• XBY = normal male• XbY = colorblind male• Cross a carrier female with a normal male.
Explain the possible offspring.
Sex-Linked Traits