Genetics Genetics Vocabulary Vocabulary Genetics- The branch of biology that studies biological inheritance.
Genetics VocabularyGenetics Vocabulary
Genetics- The branch of biology that studies biological inheritance.
Genetics VocabularyGenetics Vocabulary
Gametes = reproductive cells
SPERM EGGS
Genetics VocabularyGenetics VocabularySelf-Pollination- When pollen from a plant fertilizes an egg from the same plant (this is how pea plants normally
reproduce.)
Genetics VocabularyGenetics VocabularyCross-pollination- produces seeds that
are the offspring of two different plants. Pollen from one plant is dusted
onto the ovules of another.This allow scientists to
manipulate which plants reproduce
together.
Genetics VocabularyGenetics VocabularyTrue-breeding- if allowed to self-pollination purebred peas would produce offspring identical to
themselves.Tall pea plants only reproduce with tall
for many generations
Genetics VocabularyGenetics Vocabulary
Traits –
characteristics
Genetics VocabularyGenetics Vocabulary
Hybrids – organisms produced by crossing parents with different
characteristics
Example- crossing a tall pea plant with a short pea plant.
PugglesPuggles
Labradoodles Labradoodles
Jackapoos Jackapoos
Chiweenies Chiweenies
Genetics VocabularyGenetics Vocabulary
Genes – The factors that control traits.
Today we know these genes are
located on specific sections of DNA.
Genetics VocabularyGenetics Vocabulary
Alleles- Different forms of a gene
2 different alleles for a gene in a pea plant
•Tall or short
•Yellow or green
Genetics VocabularyGenetics Vocabulary
Dominant – the alleles that are “stronger” than others
In Pea Plants
Tall is Dominant to short.
Genetics VocabularyGenetics Vocabulary
Recessive – the weaker form of a gene
In Pea Plants
Only shows up if two are present.
Short + short = short.
Genetics VocabularyGenetics VocabularyPunnett Square – a diagram used to determine the PROBABILITY of offspring from a particular cross.
T = Tall
t = short
Genetics VocabularyGenetics Vocabulary
Phenotype – the physical characteristics of an organism
TALL
YELLOW
BLUE EYES
RED HAIR
PINK PETALS
Genetics VocabularyGenetics Vocabulary
Genotype – what an organism genetic makeup looks like
TT GGTt
gg
YY
Genetics VocabularyGenetics Vocabulary
Homozygous – has two of the same alleles.
TT GGtt
gg
YY
Genetics VocabularyGenetics Vocabulary
Heterozygous – 2 different genes
Tt GgYy
Mendel’s ConclusionsMendel’s Conclusions
The factors that control heredity are individual units known as genes. In organisms that reproduce sexually, genes are inherited from each parent.
In cases in which two or more forms of the gene for a single trait exist, some forms of the gene may be dominant and the other may be recessive.
The two form of each gene are segregated during the formation of reproductive cells.
Te genes for different traits may assort independently of one another.
Gregor MendelGregor Mendel
Gregor Mendel, a monk in the Czech Republic, is considered the "Father of Genetics", based upon experiments he conducted using garden peas. He helped lay down the principles of modern genetics.
Mendel’s ExperimentsMendel’s ExperimentsMendel was
given a garden of pure bred pea plants.
He studied various traits in pea plants
The First Generation Cross (fThe First Generation Cross (f11))
Mendel Crossed a purebred tall with a purebred
short plant and
got all tall
plants!
Step one = Define the Parents Genotype and Phenotype
XTall ShortPhenotype =
Genotype = TT X tt
The First Generation Cross (fThe First Generation Cross (f11))
ShortXTallPhenotype
Genotype TT X tt
Step two = Set up the punnett square
T T
t
t
Mendel Crossed a purebred tall with a purebred
short plant and
got all tall
plants!
Tttall
Tttall
Tttall
Tttall
Phenotype =
100 % Tall
Genotype =
100 % Tt
The Second Generation Cross (fThe Second Generation Cross (f22))
Mendel Crossed a
two heterozygous Tall
pea plants
Step one = Define the Parents Genotype and Phenotype
XTall TallPhenotype =
Genotype = Tt X Tt
The Second Generation Cross (fThe Second Generation Cross (f22))
TallXTallPhenotype
Genotype Tt X Tt
Step two = Set up the punnett square
T t
T
t
Mendel Crossed a purebred tall with a purebred
short plant and
got all tall
plants!
TTtall
Tttall
ttshort
Tttall
Phenotype =
75 % Tall: 25% short
Genotype =
25% TT; 50%Tt;
25% tt
Review Mendel’s ConclusionsReview Mendel’s Conclusions
The factors that control heredity are individual units known as genes. In organisms that reproduce sexually, genes are inherited from each parent.
In cases in which two or more forms of the gene for a single trait exist, some forms of the gene may be dominant and the other may be recessive.
The two form of each gene are segregated during the formation of reproductive cells.
Te genes for different traits may assort independently of one another.
Sample Problem #1Sample Problem #1
A yellow pod plant is crossed with a heterozygous pod plant. What is the genotype and phenotype of the offspring?
Sample Problem #2Sample Problem #2
A white flower pea plant is crossed with a homozygous recessive flower plant. What are the genotype and phenotypes of the offspring?
Sample Problems Sample Problems
A heterozygous tall plant is crossed with a homozygous tall plant. What is the genotype and phenotypes of the offspring.
Two Trait CrossTwo Trait Cross
Mendel determined that alleles assort independently from each other, even when multiple traits are studied.
Phenotype= 9:3:3:1
Genotype = 1:2:1:2:4:2:1:2:1
Common Traits Name_________________
Objective: To observe some patterns of human heredity in our classroom.
Trait
Dominant Recessive
Number of Students
Demonstrat- ing Dominant Phenotype
Number of Students
Demonstrat- ing
Recessive Phenotype
Percentage
Demonstrat- ing
Dominant Phenotype
Percentage
Demonstrat- ing
Recessive Phenotype
Tongue Roller ( R )
Nonroller ( r )
Widow’s Peak ( W )
Straight Hairline ( w )
Free Earlobes ( E )
Attached Earlobes ( e )
Dimples ( D )
No Dimples ( d )
Freckles ( F )
No Freckles ( f )
Selected Traits in Cats
Trait Dominant Allele Recessive Allele
Coat Length Short Hair (H) Long Hair (h)
Tabby Stripes Tabby (T) Stripeless (t)
Color point (markings on nose, ears, paws, and
tail)
Normal Color point
Sample Problem #1A color point cat is crossed with a heterozygous normal cat. What are the expected genotypes and phenotypes of their offspring?
The British Royal FamilyThe British Royal Family
Human traits are difficult to study for several reasons. Unlike some organisms, which produce slowly and only a few offspring at one time. Thus human traits must be studied through population sampling and pedigree analysis. A pedigree is a diagram that shows the phenotype of different generations.
Royal family tree
Pedigree for ColorBlindness – a sex linked trait