Mendels Laws of Probabilities in Offspring

1
Mendels Laws of Probabilities in Offspring

• Standard 7
• Ashley and Irum

2
Mendels Laws A History

• Gregor Mendel was born in Heinzendorf
  bei Odrau, Czech Republic. He worked as a
  gardener studying beekeeping and as a physics
  teacher in an abbey. He was known as the father
  of modern genetics. He studied about dominant and
  recessive alleles in pea plants.
• He wrote a paper called, Experiments
  on Plant Hybridization. It was published in
  1866. After peas, he studied honeybees again. He
  became an abbot in 1868, after which he
  discontinued his scientific work on account of
  his increased administrative responsibilities.

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Mendels Laws

• The Law of Segregation of Characteristics
• States that from a pair of characteristics, only
  one can be represented in a reproductive cell.

• The Law of Independent Assortment
• States that the genes for two characteristics are
  inherited independently.

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Punnett Squares

• This table represents three possible genotypes,
  along with indicating how likely a particular
  offspring of this mating is to have a certain
  genotype.
• The capital letters represents the dominant gene,
  while the lower case letters represents the
  recessive gene.

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Recessive vs. Dominant Inheritance

• The offspring of this mating can be affected,
  not affected, or carriers as shown by the table
  on the right.

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Vocabulary

• Phenotype-the appearance of an organism,
  resulting from the interaction of the genotype
  and environment.
• Genotype- the genetic make-up of an organism that
  is determined by a single trait, set of traits,
  or an entire complex of traits.
• Heterozygous-having dissimilar pairs of genes for
  any given hereditary characteristic.
• Homozygous-having identical pairs of genes for
  any given pair of hereditary characteristics.

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Whats the Difference?

• Homozygous genes are represented as either both
  capital letters (BB) or both lower case letters
  (bb).
• Heterozygous genes are represented as one capital
  letter and one lower case letter (Bb).

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QUIZ TIME!!!

• Take out your pens and paper!!!!!!!!

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1 Egyptian Mau cats are genetically crossed for
certain lengths of fur. A breeder knows that
short hair is dominant over long hair. If 75 of
the kittens are born with short hair, what are
the parents most likely genotypes?

• A the male is a heterozygous, short-haired cat,
  and the female a homozygous short-haired cat.
• B the male is a homozygous, long-haired cat, and
  the female is a heterozygous, short-haired cat.
• C the male is a homozygous, short-haired cat,
  and the female is a heterozygous, short-haired
  cat.
• D the male is a heterozygous, short-haired cat,
  and the female is a heterozygous, short-haired
  cat.

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Because the parents both have the less dominant
gene, the majority of the kittens must show the
less dominant gene as well.

• D

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2 Brown eye color is dominant to blue eye
color. A heterozygous brown eyed father and a
blue eyed mother have four children. Which
statement best describes the childrens predicted
phenotypes?

• A 50 of children will have brown eyes, and 50
  will have blue.
• B 75 of the children will have brown eyes and
  25 will have blue.
• C 75 of the children will have blue eyes and
  25 will have brown.
• D 100 of the children will have brown eyes.

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The dominance of the fathers brown eyes is
lessened because it is heterozygous, so the
blue-eyed trait stands out more than 25

• A

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3 Which genetic cross will produce all
heterozygous offspring?

• A RR x rr
• B rr x rr
• C RR x RR
• D Rr x Rr

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Heterozygous x heterozygous homozygous
Homozygous x homozygous heterozygous

• A

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4 What kind of letter represents homozygotes?

• A RR
• B Rr

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(see Whats the Difference?)

• A

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5 What kind of letter represents heterozygotes?

• A RR
• B Rr

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(see Whats the Difference?)

• B

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6 The offspring of a mating can be affected,
not affected, or ________ by a trait.

• A Re- affected
• B Determined
• C Defected
• D Carried

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Carried

• D

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7 How many Laws does Mendel have?

• A 3
• B 6
• C 2
• D 1

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2

• C

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8 What was one of Mendels Laws?

• A The Law of Conservation of Mass.
• B The Law of Segregation of Characteristics.
• C The Law of Recessiveness.
• D The Law of Intensity of Alleles.

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The 2 Laws are the Law of Segregation of
Characteristics and the Law of Independent
Assortment

• B

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9 What was Mendels first job?

• A Zookeeper
• B Biologist
• C Geneticist
• D Gardener

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Gardener

• D

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10 What was the name of Mendels paper? What
year was it published?

• A Experiments on Plant Hybridization 1866
• B Experimenting with Nature 1868
• C Experiments on Plant Hybridization 1868
• D Experimenting with Nature 1866

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He wrote a paper named Experiments on Plant
Hybridization that was published in 1866.

• A

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11 What things did he study?

• A Pea plants and human babies
• B Pea plants and honeybees
• C Chickens and lima beans
• D Garbanzo beans and lima beans

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Mendel studied the genes of Pea plants and
honeybees.

• B

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12 For what reason did he quit his studies?

• A He grew tired of genetics
• B He got Ebola
• C His father died
• D He became an abbot

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Because he became an abbot, his workload
increased and he became immersed in his
administrative responsibilities.

• D

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13 What did Mendel study as a gardener?

• A Weeds
• B Butterflies
• C Bees
• D Honey

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Bees

• C

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14 What is a Phenotype?

• A The appearance of an organism resulting from
  the interaction of the genotype and the
  environment.
• B The genetic makeup of an organism that is
  determined by a trait, set of traits, or an
  entire complex of traits.
• C Having dissimilar pairs of genes for any given
  hereditary characteristic.
• D Having identical pairs of genes for any given
  pair of hereditary characteristics.

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(see Vocabulary)

• A

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15 What is the Law of Independent Assortment?

• A It states that for a characteristic, two
  phenotypes can be present.
• B It states that the genes for two
  characteristics are inherited independently.
• C It states that genes are assorted
  independently.
• D It states that out of a pair of
  characteristics, only one can be represented in a
  reproductive cell.

38
The Law of Independent Assortment states that the
genes for two characteristics are inherited
independently.

• B