Genetics Branch of biology that focuses on heredity E? How does a punnett square predict possible offspring? E? How did Mendel

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Genetics Branch of biology that focuses on
heredityE? How does a punnett square predict
possible offspring? E? How did Mendels
experiments contribute to geneticsSB 2 c

• Heredity
• Passing of traits from parents to offspring

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Mendels Principles

• Studied 7 traits in pea plants
• Believed that there were inheritable factors
  (genes) that retain their individuality when
  transmitted from generation to generation
• Segregation pairs of genes separate during
  gamete formation
• Fusion of gametes at fertilization pairs genes
  again

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Mendels pea characteristics
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10.2 Mendelian Genetics

• The parent generation is also known as the P
  generation.

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Mendelian Genetics

• The offspring of this P cross are called the
  first filial (F1) generation.

• The second filial (F2) generation is the
  offspring from the F1 cross.

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Mendels Hypotheses

• For each inherited trait, two copies of each
  gene- one from each parent

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Mendels Hypotheses

• Alternative versions of genes
• Called alleles
• Represented by letters for a gene
• Example
• Purple P Whitep

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Mendels Hypotheses

• When two different alleles occur together
• one may be completely expressed
• Dominant
• One may not be observed
• Recessive

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Mendels Hypotheses

• When gametes are formed, alleles separate
  independently
• Each parent can give only one allele

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Representing genes

• Homozygous- (True-breeding) both alleles are
  exactly the same
• Example PP or pp
• Heterozygous- (Hybrid) alleles are different
• Example Pp

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Genotype vs. Phenotype

• Genotype
• The actual set of alleles
• PP or Pp or pp
• Phenotype
• The actual physical appearance
• Purple or white

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Mendels Laws

• Law of Dominance
• - when two alleles exist for a gene, one can be
  dominant and one recessive
• Law of Segregation
• The two alleles for a trait segregate(separate)
  when gametes are formed
• Law of independent assortment
• That alleles of different genes separate
  independently when gametes are formed

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10.2 Mendelian Genetics
Mendels Law of Segregation

• Two alleles for each trait separate during
  meiosis.

• During fertilization, two alleles for that trait
  unite.

• Heterozygous organisms are called hybrids.

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10.2 Mendelian Genetics
Monohybrid Cross

• A cross that involves hybrids for a single trait
  is called a monohybrid cross.

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Sexual Reproduction and Genetics
Mendelian Genetics
Dihybrid Cross

• The simultaneous inheritance of two or more
  traits in the same plant is a dihybrid cross.

• Dihybrids are heterozygous for both traits.

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