GENETICS

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GENETICS
1. Gregor MendelFather of Genetics
2. Genetics the scientific study of heredity
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3. Hereditypassing of traits from parents to
offspring
4. Traitsphysical or behavioral characteristics
studied in genetics.
Examples eye color, hair color, short , tall,
etc.
http//learn.genetics.utah.edu/content/begin/tour/
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1st experiment (height)
F1 generation plants then crossed
P generation plants crossed
P generation purebred tall purebred short
F1 generation- ALL plants were tall
F2 generation ¾ tall, ¼ short.
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5. Genes are the sections of DNA on chromosomes
that control traits.
6. Alleles are different forms of a gene pair.
Each one of the pair is an allele. Each organism
inherits a combination of two alleles - one from
each parent.
Individual alleles control the inheritance of
traits. Some are dominant and others are
recessive.
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7. A dominant allele is one whose trait always
shows up in the organism when the allele is
present. It blocks another genetic factor.
Ex. Brown eyes
8. A recessive allele is blocked , or covered up,
whenever the dominant allele is present.
Ex. Blue eyes
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Dominant and recessive traits are represented
by using letters. 9. Dominant traits are
represented by capital letters. 10.Recessive
traits are represented by lower case letters.
Example B brown hair b red
hair
BB brown hair / purebred Bb brown hair /
hybrid bb red hair / purebred
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11.Purebred (True-bred)An organism that always
produces offspring with the same form of a trait
as the parent. Also known as homozygous.
Example Purebred blonde haired parents will
always have blonde haired
children.
12. In Mendels experiments, P stood for the
parent generation, F1 stood for the first
generation, and F2 stood for the second
generation.
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13.HybridAn organism that has two different
alleles for a trait. ALSO known as
heterozygous.
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14.Homozygousan organism that has 2 identical
alleles for a trait Example BB homozygous for
brown hair bb homozygous for
red hair
15.Heterozygousan organism that has two
different alleles for a
trait Example Bb heterozygous for brown
hair there cannot be a hetero red
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16.Phenotypephysical make-up of an organism
you can actually see phenotype
Ex. -- Tall and short. 16
17.Genotypegenetic make-up of an organism
you cannot see genotype Ex.
-- BB, Bb, bb
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Punnett SquareA chart used in genetics to show
all the possible combinations of alleles.
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Teach how to work punnett squares !
worksheets
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• Chromosomes are
• located inside the nucleus of cells.
• made of DNA which carries genetic information
  from parent to offspring.

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Chromosome Theory The chromosome theory states
that genes are carried from parents to their
offspring on chromosomes. Chromosome theory was
developed by an American geneticist, Walter
Sutton, who studied grasshopper cells. Both
parents contribute chromosomes to the offspring,
but in order for the offspring to have the
correct number of chromosomes in the end, each
parent may only contribute one-half the total
needed.
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The number of chromosomes determine the type of
organism!!

• Humans have 46 total chromosomes.
• 23 in each sex cell.
• Grasshoppers have 24 chromosomes.
• 12 in each sex cell.
• Dogs have 78 chromosomes.
• 39 in each sex cell.
• House flies have 12 chromosomes.
• 6 in each sex cell.

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DNA is the genetic material that carries
information about an organism and is passed
from parent to offspring.
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Meiosis the process by which the number of
chromosomes is reduced by half to form sex
cells. sperm from the male egg from the
female.
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During meiosis 1. the chromosome pairs
separate, and 2. are distributed to four
different cells. The resulting sex cells have
only half as many chromosomes as the other cells
in the organism.
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Each gene pair has an allele from mom and an
allele from Dad.
You have 23 pairs of chromosomes per cell. Each
parent contributes one half of the pair. Each
chromosome contains thousands of genes.
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Gene a segment of DNA on a chromosome that codes
for a specific trait.
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Mutationany change in a gene or chromosome.
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Mutations

• A mutation is any permanent change in the
  sequence of DNA in a gene or a chromosome of a
  cell.
• If mutations occur in reproductive cells, they
  can be passed from parent to offspring.
• Cancer, diabetes, and birth defects all result
  from mutations in genes.

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Inheritance of Disease

• A pedigree shows genetic traits that were
  inherited by members of a family.
• This illustration shows the pedigree for a family
  in which cancer was common in each generation.

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Lesson 2 - VS

• Scientists use Punnett squares and pedigrees to
  predict and analyze genetic outcomes.

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Selective Breeding
Selective breeding is the process of selecting a
few organisms with desired traits to serve as
parents of the next generation. People use
selective breeding to increase the value of
plants or animals, such as fruits or vegetables
or dairy cows.
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Examples of selective breeding

• Inbreeding crossing two parents that have
  identical or similar sets of alleles.
• Ex Purebred horses with exceptional speed
  are crossed to produce offspring to run very
  fast. Purebred dogs are crossed to maintain
  hunting skills.

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2. Hybridization the crossing of two
genetically different parents for getting the
best traits from both parents. Ex Farmers
cross the corn that have the sweetest kernels
with a parent that is disease resistant.
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3. Cloning - A clone is an organism that is
genetically identical to the organism from which
it is produced.
Example A cutting from a plant that grows a
new plant is genetically identical to the mother
plant.
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Advantages and Disadvantages of Purebreds
Hybrids

• Purebred advantages include
• Working animals perform better
• Food animals produce better tasting foods
• Plants may have higher yields
• Plants may have better tasting foods

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• Purebred disadvantages may include
• Inbreeding increased the probability of genetic
  disorders
• Purebred species are more expensive
• Plants may produce unattractive foods
• Plants may not have disease resistance

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• Hybrid advantages include
• Food animals able to produce more food
• Plants may have higher disease resistances
• Plants may have more curb appeal (attractive
  appearance, better shipping, etc.)
• Animals may have larger litters and better
  survival rates for the young

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• Hybrid disadvantages include
• May not always get the desired trait
• May be more expensive to produce seeds may not
  always have high viability
• May not taste as good as purebred

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• Scientists today are using what they have learned
  about genetics to help people.
• In genetic engineering, the genetic material of
  an organism is modified by inserting DNA from
  another organism.

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Genetic Engineering
Genetic Engineering is the transfer of genes
from one organism into the DNA of another
organism. This is also called gene splicing.
because the DNA molecule is cut open and a gene
is spliced into it. Usually involves bacteria.
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Examples of benefits of genetic engineering.
It can produce medicines such as insulin for
diabetics. It can improve food crops by making
them more tolerant to certain conditions
drought, frost, It may be used one day to
replace genes for curing genetic diseases.
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Bacteria have been genetically engineered to
produce human insulin.
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Human Growth Hormone(Sisters )