Download 11-1 The Work of Mendel

Chapter 11: Introduction to Genetics
11-1 The Work of Mendel
• What does every living thing inherit from their parents?
• Genetics – __________________________________________________
Look around at your classmates and make a list of some of the traits that
are inherited. _______________________________________________
__________________________________________________________
What did Mendel already knew …
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Each flower produces ____________ and _____________
Cross fertilization (sexual) – ___________________________________
Self-pollination (asexual) – ____________________________________
Mendel’s pea plants were __________________________
– A tall plant with green seeds would produce a ____________________________
Genes, Alleles and Dominance
• Trait – _____________________________________________________
– Mendel studied 7 different pea plant traits
• What are some examples? _________________________________________
Genes, Alleles and Dominance
____________ – the chemical factors that determine traits (the segment
of DNA) ex. pea plant: height
different forms of a gene from each parent ex. pea plants:
tall and short (T or t)
_______________ –
Principle of Dominance
• Principle of dominance: ______________________________________
___________________________________________________________
• Dominant allele – ____________________________________________
– Capital letter (T=tall)
• Recessive allele – ____________________________________________
___________________________________________________________
– Lower case letter (t=short)
• Heterozygous – _____________________________________________
• ______________________ for that trait
• Ex: Tt
• Homozygous – ______________________________________________
___________________________________________________________
• ____________________ for a particular trait
• Ex: TT or tt
• Phenotype – __________________________
• Ex: ____________________________________
• Genotype – ___________________________
• Ex: _____________________________________
• Tall plants have the same ______________ (tall), but not the same
________________ (TT or Tt)
• Why are TT and Tt genotypes for tallness, but tt is not???
11-2 Probability and Punnett Squares
•Mendel realized…the principles of ______________ could be used to
explain the results of genetic crosses.
Genetics and Probability
• Probability – ________________________________________________
• Ex: probability of flipping a coin to heads = ½ or _____%
• Probability of head 3 times in a row = ½ x ½ x ½ = _____
• The ________ the number or trials, the closer to the expected ratio
• _______ outcomes do not affect _______ outcomes
• Alleles segregate randomly (like a coin)
Principle of Segregation
• Segregation = _____________________
• The alleles for tall vs. short separate
during the formation of __________________ – sex cells
• Each gamete carries
________________________
The Two-factor Cross: F1
• ____ alleles (2 genes) at the same time
• Provides the __________ plants (F2 generation)
• Crossed a homozygous ________ (round yellow peas) with a
homozygous________ (wrinkled, green peas)
11.3 Beyond Dominant and Recessive - Other Patterns
of Inheritance
Genes can act in various ways
• Dominant vs. Recessive – ____________________________________
• Incomplete Dominance
•
Definition : _____________________________________________________
Ex: flowers – white x red flowers = _________ flowers
• Codominance
• Definition: _______________________________________________________
Ex: chicken feather – black and white alleles = __________________________
Colors don’t _________ like incomplete dominance
•Multiple Alleles
• Definition: __________________
_____________________________
• (more than 2 alleles exist in a
population not an individual)
Ex: rabbit’s coat color
Ex: human’s _______________
• Polygenic Traits
• Definition: _______________________________________________
Ex: fruit fly red eyes ____________________________________________
• Diff. combo of genes produce different eye colors
Ex: Human _______ color – more than 4 different genes
Human ________ – more than 50 genes
11.3 Genetics and the Environment
• Genes provide a plan for development, but how the plan unfolds also
depends on the environment:
• Ex. Butterflies have different wing colors depending on ___________
_______________
• Ex. Hydrangea flowers are different colors depending on __________