Transcript Document

A quick look back at Protein Synthesis:
Genes and Heredity
• “You’re a chip off the old block!”
• The apple didn’t fall far from the
tree.”
• What observations led to
speculation that characteristics are
inherited?
Traits are controlled by genes on chromosomes. Your
traits are the result of the interactions of the genes of
both parents.
Hybrids: offspring that differ from the parent in one or
more traits.
Mendels Experiments.isf
Mendel’s Experiments
• Characteristics
Characteristics Dominant trait
Recessive Trait
Seed shape
Seed colour
Pod shape
Pod colour
Flower colour
wrinkled
Green
constricted
yellow
white
Round
Yellow
Inflated
Green
Purple
Dominant and recessive
• Dominant trait: genes that determine the
expression of the genetic trait in the
offspring
• Recessive trait: genes that are overruled by
dominant genes
Mendel’s Laws of Heredity
• The passing of traits from parents to offspring is
called heredity.
• traits are the result of interactions of the genes of
both parents.
• 1. Inherited characteristics are controlled by
factors called genes
• 2. One gene masks the effects of another.
Principle of dominance
• 3. A pair of factors or genes, segregate during the
formation of gametes – law of Segregation.
How Mendel showed traits being
passed on.
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Dominant trait -- capital letter R
Recessive trait- lower case r
Traits occur in pairs:
RR, Rr, rr
Gene for seed shape: allele-R = round
allele -r = wrinkled
Dominant vs Recessive Humans
Autosomal traits