Chapter 11 Observable Traits of Inheritance
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Who is the father of Genetics?
Mendel’s Experimental Approach
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___________________________ suggested that a population could evolve if members showed
variation in heritable traits
___________________ that improved survival chances would be more common in each
generation –in time, population would change over time or evolve
Gregor Mendel used experiments in __________________ and a knowledge of mathematics to
form his hypothesis
He used green __________________ in his experiment
This plant can _________________ itself
_______________ (white flowerwhite flower) ---Self Ferilization
Cross-fertilized :
Mendel crossed-fertilized true-breeding garden pea plants having clearly ___________________
traits (hybrid)
Genetic Terms
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Genes
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Locus
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Homologous Chromosome
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Alleles
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True-Breeding
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Hybrid
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Homologous alleles
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Homozygous Dominant
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Homozygous Recessive
Heterozygous
o
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Heterozygous Dominant
Dominant
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Recessive
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Genotype
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Phenotype
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P Generation
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F1 Generation
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F2 Generation
Mendel’s Laws of Heredity (Law of segregation)
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Law of Segregation:
Monohybrid Crosses
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Monohybrid crosses have two parents that are ____________________ for contrasting forms of
a trait
Self-fertilization:
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We know now that all members in the second generation are ___________________
F2 Generation:
Steps to Monohybrid Cross (Copy from Board)
Testcross
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To support his concept of segregation, Mendel crossed F1 plants with
_______________________ individuals
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A _________________ ratio of recessive and dominant phenotypes supported his hypothesis
Mendel’s Law of Inheritance (Law of Independent Assortment)
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Law of Independent Assortment:
Dihybrid Cross: Steps found on the board
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Incomplete Dominance:
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Codominance:
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o Example
Multiple Allele System
Interactions between gene pairs
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__________________: One gene pair can influence other gene pairs, with their combined
activities producing some effect on phenotype
o Examples:
Hair Color in Mammals
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In Labrador retrievers, one gene pair codes for the ______________________ produced while
another codes for ______________________
Another ______________________ determines whether melanin will be produced at all
Comb Shape in Poultry
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Sometimes interactions between ___________________ results in a phenotype that neither
pair can produce alone
Comb shape in chickens is of at least _____________ depending on the interactions of
_______________ pairs
Regarding the Unexpected Phenotypes
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Tracking even a __________________________ through several generation may produce results
that are different
_____________________________ (Immobile, bent fingers) can express itself on both or one
hand because a possible gene product is missing
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Polygenic Traits
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Traits expressed by more than ____________
__________________________ (Three genes play a role of eye color)
Environmental Effects
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Fur on extremities of certain______________________________ will be darker because the
enzyme for melanin production will operate at cooler temperature but is sensitive to heat on
the rest of the body.
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Hydrangea Plants: