Introduction to Genetics

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Mr. Matthews Policy

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Mr. Matthews Policy

• Reinforcement - A quiz may be offered at anytime
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Mr. Matthews Policy

• Responsibility - I expect you to read the section
  of the chapter before coming to class. I dont
  expect you to know everything in the chapter, but
  this will help you understand the information
  presented in class. This is the key to getting a
  good grade without trying very hard. How? It will
  reduce your study time. Try it.

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Mr. Matthews Policy

• Regurgitation If you have read up on the lesson
  note-taking is just jotting down the blurry
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  sections, note-taking will be a nightmare for you
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  am speaking from years of experience of failing,
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The Magic Formula

• Your Effort My Guidance Good Grades

Bring you textbook to class and a notebook for
note-taking!
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Introduction to Genetics

• Chapter 9
• Section 9-1

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Unit Outline

• Introduction Mendel and his experiments
• Genotype, phenotype and probability
• Monohybrid crosses
• Dihybrid crosses
• Cloning

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Genetics
Trait a category within which alternative
characteristics, such as hair color or height,
can be observed. Heredity- the transmission of
traits from parents to their offspring. Gene- a
segment of DNA that is a unit of hereditary
information.

• the field of biology devoted to the
  understanding of how traits are passed from
  parents to offspring

What is a gene?
What is a trait?
What is heredity?
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Mendels Experiments

• Garden Peas
• Seven Traits
• Plant height (long or short stems)
• Flower position along the stem (axial or
  terminal)
• Pod color (green or yellow)
• Pod appearance (inflated or constricted)
• Seed texture (smooth or wrinkled)
• Seed color (green or yellow)
• Flower color (purple or white)

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Mendels Methods

• What is Pollination?
• Self-pollination?
• Cross-pollination?

Transfer of pollen from an anther (male part) to
a stigma (female part)
Pollination of the same blossom on the same plant
anthers
Transfer of pollen from one plant of another
plant.
stigma
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Mendels Notes

• Pure-breeding (True-breeding) -
• Mendel discovered that plants that were pure for
  a trait always produced offspring with that
  trait. (Strain)
• (Pea plants with a pure trait for yellow pods,
  produced yellow pods)
• How did he know they were pure? He allowed a
  number of generations of the plants to
  self-pollinate.

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P1 generation Parental generation F1 generation
First generation of P1 generation (F
filial) Dominant trait a factor that masked or
was dominant to another factor Recessive trait
a factor that is masked by another factor
X
P1
F1
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Law of Segregation

• a pair of factors is segregated, or separated,
  during the formation of gametes.

gene
Gene- a segment of DNA that is a unit of
hereditary information.
Allele- an alternative form of a gene
allele
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Law of Independent Assortment

• factors for different characteristics are
  distributed to gametes independently.

These genes may be far apart on the chromosome,
or on different chromosomes.
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The Breakdown

• The study of how characteristics are translated
  from parents to offspring is called ________.
• ____________ is when pollen is transferred from
  the anthers of a blossom to either the stigma of
  the same blossom or the stigma of another blossom
  on the same plant.

genetics
Self-pollination
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The Breakdown

• ______________ occurs when pollen is transferred
  between flowers of two different plants.
• Mendel concluded that inherited characteristics
  are controlled by factors that occur in pairs. In
  his experiments on pea plants, one factor in a
  pair masked the other. The trait that masked the
  other was called the ________ trait. The trait
  that was masked was called a ________ trait.

Cross-pollination
dominant
recessive
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The Breakdown

• We now know that the factors that Mendel studied
  are _______, or alternative forms of a gene.
• The _______________ states that a pair of factors
  is segregated, or separated, during the
  formation of gametes.
• The __________________________ is observed only
  for genes that are located on separate
  chromosomes or far apart on the same chromosome.

alleles
Law of Segregation
Law of Independent Assortment
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The Breakdown

• The Law of Independent Assortment states that
  factors for different characteristics are
  distributed to ________ independently.
• (Hint during phase I of meiosis, homologous
  chromosomes randomly migrate to opposite sides of
  the dividing cell.)

gametes
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Genetics Career

• Salaries in the genetics field vary widely,
  depending on where a geneticist works. For
  example, geneticists working at a university as a
  professor would have a typical academic salary.
  Assistant professors make average salaries in the
  range of 50,000-75,000 range while associate
  professors make average salaries ranging from
  60,000 to 90,000. Experienced geneticists
  working in industry, at biotechnology firms and
  pharmaceutical companies, can earn much more than
  this, in the 100,000-150,000 range.

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Review Questions

• Complete section 9-1 review questions one through
  six on page 169.

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Next Class

• Read Section 9-2 Genotypes, Phenotypes, and
  Probability