Transcript Mendel Powerpoint File

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Heredity
Passing on of characteristics
from parent to offspring
Genetics
The scientific study of
heredity
Gregor Mendel
• Born in 1822
• Studied science and
mathematics in Vienna
• Became a priest –
taught science
• Managed monastery
garden
• Studied true–breeding pea
plants
• Always pass characteristics
to their offspring when self pollinate
• Tall plants have tall
offspring, and green pods
produce green pods
• SELF-POLLINATION : pollen
fertilizes egg on the same flower
(how most normally reproduce)
• CROSS-POLLINATION : pollen
on 1 plant fertilizes egg on
another plant (2 parents, what
Mendel did)
•Trait: characteristics
that vary from one
individual to another
•Ex: shape, color, height
•Each trait has 2 types
(round vs. wrinkled, or yellow vs. green)
GENE - chemical factor
that determines traits
Allele - different forms of
a gene
•Mendel found 2 alleles for
each pea plant
DOMINANT recessive
A trait that you A trait that
observe
vanishes
Shown with a Shown with a
capital letter
lower case
letter
EX: T = tall
EX: t = short
Tall = TT or Tt
Short = tt
Phenotype -
outward/
physical appearance of an
organism
Ex: tall vs. short
Genotype - genetic
combination of an organism
Ex: TT, Tt or tt
Homozygous
• The two alleles are the same
• EX: TT or tt
Heterozygous
• The two alleles are different
• EX: Tt
F1 Generation
F1 Generation
• Mendel crossed two pea plants
with opposite traits to produce
hybrids
• Hybrid - offspring of parents
with different traits
• Trait of only one parent is seen
F2 Generation
F2 Generation
• Cross the plants of the F1
generation
• Trait that disappeared in the
F1 generation reappears
(only seen ¼th of the time)
The Law of Segregation
and the
Law of Independent Assortment
Segregation
–Process that separates the two
alleles (ex: Tt) of a gene during
gamete formation (meiosis)
Independent Assortment
–genes are inherited
independently of each other
Selective breeding
Allowing only those plants
and animals with desired
characteristics to produce the
next generation of offspring
(ex: farm crops, livestock and pets)
Hybridization
Crossing dissimilar individuals to
bring together the best of both
organisms (ex: horse and donkey
to produce a mule)
Inbreeding
Continued breeding of individuals
with similar characteristics
(usually related members of a species)
1.Preserves traits of the species
2.Increased chance of inheriting
recessive genes (causes genetic
diseases/disorders)
Genetic Engineering
Making changes in the DNA code of a
living organism
Transgenic
Contains genes from other species
(Ex: human insulin produced by
bacteria)
Clone
Member of a
population of
genetically
identical cells
produced
from a single
cell
Karyotype
Picture of chromosomes arranged in pairs
1.sex chromosomes –
pair #23 that determine
the sex of an individual
(XX or XY)
2.autosomes (autosomal
chromosomes) – the
remaining 22 pairs of
chromosomes
Pedigree
Chart which shows the relationships
within a family (used to help
determine if a trait will be passed on)