Jan 27 Mendel
Transcript of Jan 27 Mendel
January 27Learning Target: I will• Identify the father of
genetics• Define and give an example
of a dominant allele• Define and give an example
of a recessive allele
Homework:• Vocab cards, text page 170-
176, 183-184
Agenda:• Check homework (text
176 #1-4)• Mendel Cornell Notes• Which traits are
dominant? NB-85
DO NOW:• Fill out your weekly
planner (NB-84)
Homework vocab cards,Text pages 170-176, 183-184
• Incomplete Dominance
• Codominance• Polygenetic Traits• Multiple Alleles• Dominant Allele
• Recessive Allele• Genetics• Heredity• Trait• Mendel
Let’s go over the vocabulary
DNA
Chromosome
• A compacted form of DNA
Gene
• A strand of DNA that codes for a protein, and, therefore, a trait
Trait
Fur color
Eye color
Fur length
• A characteristic of an individual that is inherited
Allele
• A different version (form) of the same gene, such as eye color
Heredity
• The passing of traits (characteristics) to offspring (babies).
Genetics
• The study of heredity.
Mendel, Gregor
• An Austrian monk, who is often called the father of genetics
True Breeding
• A plant which, when self-fertilized, always produces offspring identical to itself
Self-fertilization
• When a plant pollinates itself, so its own male and female gametes form another plant. (This happens a lot)
Cross-fertilization
• Fertilization of one plant by the pollen of another plant
Dominant Allele
• The allele that is always observed in an organism, even a heterozygote
Dark hair = B
Light hair = b
Recessive Allele
• The allele that is masked by the dominant allele
Dark hair = BLight hair = b
Monohybrid Cross
• A hybrid that is created from two parents that differed by only one trait
Punnett Square
• A table that demonstrates the resulting offspring from mating two individuals
Genotype
• The specific genes that an organism has
• We give them letters, such as Bb
Phenotype
• An observable trait
Brown color
DNA Quiz Results
• 8+ =A• 7.5 =B• 6.5-7 =C
NB-85Which traits are dominant?
Trait Class Ratio Class Guess Real AnswerEarlobes FREE FREE
Widows Peak NONE WIDOWS PEAK
Dimples DIMPLES DIMPLES
Thumbs CURVED STRAIGHT
Pinky STRAIGHT
Mid-digit Hair
NONE
Toe length SHORTER
Tongue-roll ROLLER ROLLER
An Introduction & HistoryAdapted from Stacey Calvert, Central Middle Schoolhttp://www.wayzata.k12.mn.us/cms/index.php?option=com_content&task=view&id=199&Itemid=44
Four O’clock Flowers were one example..
He crossed a white flower..
Mendel got some interesting (but different) results when dealing with other species of plants..
+..with a white flower
Guess what he got???
You don’t seem shocked..
either wasMendel!
Mendel kept up the experiment..(He knows the Scientific Method!)
This time..
He crossed a RED plant..
+..with a RED plant
Any guesses??
Okay, then!-->
are you allstill with me?
“I am!”
Mendel THEN CROSSED..
A WHITE flower
+
with a RED flower
Feel lucky?..do ya??
He kept it going!-->“Let’s get the party started”
Incomplete Dominance
• Dominant allele cannot completely cannot completely maskmask the expressionof another– Example: redred
snapdragons crossed with whitewhite ones yield pinkpink.
Codominance• Both alleles of a gene
contribute to the phenotype of an organism– Example: whitewhite horses
bred with red horses yield roan horsesroan horses, a mix , a mix of white and redof white and red.
– The picture should show R as red and W as white.
• Example of polygenetic heredity– A and B alleles = CODOMINANTCODOMINANT– O allele = RECESSIVERECESSIVE
Blood Groups
Single Effect of Multiple Genes
•• PolygenicPolygenic– Several genes
produce ONE phenotypic result
• Continuous Variation
–– Skin colorSkin color– HeightHeight