Geneticsstudent2007

Genetics Vocabulary

Genetics- The branch of biology that studies biological

_______________________.

Genetics Vocabulary

Gametes = _______________ cells

SPERM EGGS

Genetics VocabularySelf-Pollination- When

______________ from a plant ______________________ an egg

from the same plant (this is how pea plants normally reproduce.)

Genetics VocabularyCross-pollination- produces

_______________ that are the offspring of two different plants.

Pollen from one plant is dusted onto the ____________ of another.

This allow scientists to

manipulate which plants reproduce

together.

Genetics Vocabulary

True-breeding- if allowed to self-pollination

______________ peas would produce offspring

______________ to themselves.

Tall pea plants only reproduce with tall for

many generations

Genetics Vocabulary

Traits –

_______________

Genetics Vocabulary

Hybrids – organisms produced by __________________

parents with different _____________________

Example- crossing a tall pea plant with a short pea plant.

Genetics Vocabulary

Genes – The factors that ____________________ traits.

Today we know these genes are

located on specific sections of DNA.

Puggles

Labradoodles

Jackapoos

Chiweenies

Genetics Vocabulary

Alleles- Different forms of a _______________________

2 different alleles for a gene in a pea plant

•Tall or short

•Yellow or green

Genetics VocabularyDominant – the alleles that are

“________________” than others

In Pea Plants

Tall is Dominant to short.

Genetics VocabularyRecessive – the

________________ form of a gene

In Pea Plants

Only shows up if two are present.

Short + short = short.

Genetics Vocabulary

Punnett Square – a diagram used to determine the

____________________ of offspring from a particular cross.

T = Tall

t = short

Genetics Vocabulary

Phenotype – the physical characteristics of an organism

TALL

YELLOW

BLUE EYES

RED HAIR

PINK PETALS

Genetics Vocabulary

Genotype – what an organism genetic makeup looks like

TT GGTt

gg

YY

Genetics Vocabulary

Homozygous – has two of the same alleles.

TT GGtt

gg

YY

Genetics Vocabulary

Heterozygous – 2 different genes

Tt GgYy

Gregor 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 Experiments

• Mendel was given a garden of pure bred pea plants.

• He studied various traits in pea plants

The First Generation Cross (f1)

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 (f1)

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!

Phenotype =

Genotype =

The Second Generation Cross (f2)

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 (f2)

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!

Phenotype =

Genotype =

Review Mendel’s Conclusions• The factors that control heredity are individual units known

as genes. In organisms that reproduce _________________, genes are inherited from each parent.

• In cases in which two or more forms of the gene for a single ___________ 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.

• Two genes for different traits may ___________ _____________________ of one another.

Sample Problem #1

A yellow pod plant is crossed with a heterozygous pod plant. What is the genotype and phenotype of the offspring?

Sample 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 Problem #3

A heterozygous tall plant is crossed with a homozygous tall plant. What is the genotype and phenotypes of the offspring.

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 #4A color point cat is crossed with a heterozygous normal cat. What are the expected genotypes and phenotypes of their offspring?

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 #5A homozygous tabby cat is crossed with a stripeless cat. What are the expected genotypes and phenotypes of their offspring?

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 #6A heterozygous short haired cat is crossed with another heterozyogous cat cat. What are the expected genotypes and phenotypes of their offspring?

Trait Number of Students Demonstr

at-ing Dominant

Phenotype

Number of Students Demonstr

at-ing

Recessive Phenotype

PercentageDemonstrat-

ingDominantPhenotype

PercentageDemonstrat-

ingRecessivePhenotype

Dominant Recessive

TongueRoller ( R )

Nonroller ( r )

Taster ( T )

Non-Taster ( t )

FreeEarlobes ( E )

AttachedEarlobes ( e )

Dimples ( D )

NoDimples ( d )

No 2nd joint finger hair

( F )

2nd joint finger Hair

( f )

Two 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

The 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