Dominant

• An allele that masks the presence of another allele

Ex. Aa is a heterozygous dominant genotype

Ex. AA is a homozygous dominant genotype

“A” is the dominant allele and “a” is the recessive allele

Recessive

• An allele that is dominated by the other, over expressed by another

ex. aa is recessive

• “A” is the dominant allele and “a” is the recessive allele

Phenotype

• The external appearance of an organism that is determined by the individual genotype

Different phenotypes of the shells

Genotype

• The pair of alleles that determine a specific trait.

• Ex: In Aa, the allelles are A and a

Punnett Square

• A model used to establish the probabilities of the results of a genetic cross

AA

aa

Homozygous

• Referring to a gene pair in which the two alleles code for the same trait

• “Homo” means “same”

• AA or aa are homozygous genotypes

Heterozygous

• Referring to a gene par in which the two alleles do not code for the same trait, two different alleles

• “Hetero” means “different”

• Ex: Aa is a heterozygous genotype

Alleles

• Alternative form of a gene, there are two

Dominant A

Recessive a

Monohybrid Cross

• A cross between individual that involves one pair of contrasting traits

Practice problem

If a person is homozygous dominant for Brown eyes and marries someone who recessive for Blue eyes, can they have a blue eyed child? What % will be heterozygous brown?

Person 1: BB= homozygous brownPerson 2: bb= recessive for blue

BB x bb B B b Bb Bb b Bb Bb

• No blue eyes childern, 100% heterozygous brown* O will be homozygous brown

Dihybrid Cross

• A cross between individuals that involves the pairing of contrasting traits, two sets of alleles.

Practice Problem

If a Tall (TT) Green(GG) pea plant is crossed with a Short(tt) yellow(gg) plant, What portion of the offspring will be tall and yellow?

TTGG crossed with ttgg is a dihybrid cross( 4 x 4 square)

TG TG TG TGtg tgtg ALL will be TtGg, Tall and Greentg

Sex Linked

• A trait carried on only the x chromosomes

XHY male with trait

XhY male without trait

XHXH female without trait

XHXh female without trait carrier

XhXh female without trait carrier

Incomplete Dominance

• The inheritance relationship that occurs when both alleles influence the phenotype

If this was not an incompleteTrait, there would have been3 tall and 1 short

Codominance

• When neither of two alleles of the same gene totally masks the other, they are both expressed at the same time.

• More than one dominant allele

RR= Red flower

rr= White flower

Rr= Red and White flower

Polygenic

• A trait controlled by multiple genes

Ex: eye color. There is not one gene that determines eye color, but several.

Multiple alleles

• When more than alleles code for one trait

Ex: Blood types

Alleles are A, B , and o Three alleles

AA= type ABB= type BOO=Type O recessiveAB = Type AB (both are dominant

Pedigree

• A diagram of the genetic history of an individual, a family tree

Practice Pedigree

Aa

AaAa or AA

Aa

Aa

aa

aa

aa

What genotype must I-I and I-2 be? Why?

I

II

IIIWhy do the parents 1-I and 1-2 not have the disorder, but two children do?

Biotechnology

• Technology used to manipulate DNA, proteins,RNA and such.

• EX: cloning, DNA fingerprinting, DNA and protein sequencing.

Gene Splicing

• Splicing of two genetic codes

• Taking a piece of DNA and moving it, removing it, or replacing it.

Electrophoresis

• Using electricity to separate DNA on an agarose gel. DNA can be visualized a a set of bands that were cut by enzymes.

• DNA is “cut” with enzymes to produce fragments.• The band run through the getl according to size. Small

bands travel faster than larger ones.

Cloning

• Process of removing DNA from one organism and putting it into another.

• EX: the gene for insulin is removed from a pig or human and inserted into E.coli bacteria. The E. coli then produce the insulin that is purified , bottled, and distributed to people in need. The insulin was “cloned”

Genetic engineering

• A form of applied genetics in which scientists directly manipulate genes

DNA Fingerprinting

• A pattern of bands made up of specific fragments from a individual's DNA. The bands are produced by putting enzymes or “moleculer scissors” in with the DNA. These enzymes cut the DNA at specific sequences producing smaller fragments. These fragments can be visulaized by DNA electrophoresis.

http://www.biotech.iastate.edu/biotech_info_series/bio6.html

1. The physical expression of one’s genes is called their

a. alleles

b. genotype

c. phenotype

d. genes

2. The unseen genetic make-up of an individual is called

a. alleles

b. genotype

c. phenotype

d. genes

3. When someone has two identical alleles they are called

a. recessive

b. homozygous

c. heterozygous

d. dominant

4. When someone has two different alleles they are called

a. recessive

b. homozygous

c. heterozygous

d. dominant

5. In the space below, create a punnett square between a homozygous recessive and heterozygous organism:

A a

a

a

Aa

Aa

aa

aa

6. Scientists have altered crop plants to make6 them more resistant to insects and disease. Which of these processes makes it possible for scientists to alter plants:

a. natural selectionb. gene splicingc. adaptationd. chemosynthesis

7. In humans, the allele for dimples (D) is dominant. The allele for not having dimples (d) is recessive. A woman (DD) and a man (Dd) have four children. Which of these is the predicted ratio of the children with dimples to the children without dimples?

a. 1:0

b. 1:1

c. 1:3

d. 3:1

8. Which of these combinations results in the expression of a recessive trait?

a. two dominant alleles

b. a dominant sex-linked allele and a Y chromosome

c. two recessive alleles

d. a dominant allele and a recessive allele

9. Which of these explains how two taster parents could produce a nontaster child?

a. Both parents are heterozygous and produce a homozygous recessive child

b. Both parents are homozygous recessive and produce a homozygous dominant child

c. Both parents are heterozygous and produce a heterozygous child

d. Both parents are homozygous dominant and produce a homozygous recessive child

10. Based on the data the students collected, the allele for tasting PTC is most likely

a. dominant

b. heterozygous

c. recessive

d. sex-linked

11. A woman that is homozygous dominant for having a widow’s peak and a man that is heterozygous for having a widow’s peak have a child. What is the probability that their child will have a widow’s peak?

A A

A

a

AA AA

Aa Aa

The Probability is 100%

What are the genotypes and phenotypes of the parents?

Parent 1 genotype=____________ phenotype=___________Parent 2 genotype= ____________ phenotype= _____________

The possible phenotypes and genotypes of the children? Genotypes: _________________________Phenotypes:_________________________

AAWidow’s Peak

Aa

Widow’s Peak

50% AA or 50% Aa

All Widow’s Peak