11/21 Genetics: Dihybrid Crosses

Dihybrid crossing is when you cross two different traits. In this example, we crossed two butterflies. Each butterfly's genotype was AaBb.

A=black body          B=spots

a=white body           b=no spots

11/18 Genetics: Monohybrid Crosses

Genes

1. DNA

goes through transcription- RNA polymerase 

2. mRNA- processing... introns out/cap and tail

goes through translation- ribosome (5-3)/tRNA bus system

3. Amino Acid

4. Polypeptides- proteins make traits 

Physical and biochemical (inside of you)

Example. lactase- enzyme

break down lactase

Lactose intolerant -no lactase

gene malfunction: mutation, point base, deletion, insertion (jumping genes)

Traits "Alleles"

Dominant- always shows (A_)

Recessive- (Aa)

2 types of cells 

Somatic- body cells

Mitosis: cell division 23 pairs(1/2 mom 1/2 dad) creating identical daughter cells (DNA replication)

Gametic- sex cells (gender)

Meioses

Mendel

pea plants 

traits- smooth or wrinkle 

color: green/yellow

shape

height: tall/dwarf

flower color 

Ratios

-math data 

"trends" something being passed

-didn't know DNA

Vocab 

homozygous- same AA(p2) aa (q2)

heterozygous- different Aa (2pq)

dominant- A_

recessive- aa

phenotype- physical traits

genotype- genes Aa (letters)

F1- first offspring/generation

     carrier or hybrid- heterozygous

     pure- homozygous

Backcross- F1 mate w/parents

11/13 Unit 3 Test

We had the test today!!!!!!!!!!!!!!!!!!
swaggie

11/11 (Make a Wish) The Operon System

The operon system goes through the replication process.
Heres a recap of replication
First, helicase breaks the hydrogen bonds
RNA primase goes in with its RNA nucleotides and adds an OH- to the 3 prime side to make it polar
DNA Poly III reads it
DNA Poly I replaces RNA nucleotides with DNA nucleotides
Lastly, DNA Ligase goes in and fills those fragment gaps with phosphodiester bonds

Operon System- regulatory gene creating a key

Trp Operon System (creating Amino Acid Trp)
DNA goes through transcription, mRNA goes through translation and creates a protein
The protein is the key (repressor) to unlock the door (the operator)
The RNA polymerase reads it
Tryptophan is made
This whole area of the system is the promoter (open door)

Lactose Operon (Creating enzyme lactase; disaccharide)

Glucose and Galactose- we cannot digest

Protein is inserted with Allolactose (inducer) which makes it inactive 

The protein unlocks from operator and the RNA polymerase is able to read it and make Lactase

11/6 Snork Lab

Today we analyzed a Snork's genes of its DNA and determined the traits of the Snork based off of that. Protein Synthesis determines the physical or chemical trait.

Protein Synthesis in order-
Gene
DNA
mRNA
Amino Acid
Polypeptide
Protein (gives us trait)
Enzyme

Example of what we did-
We converted the DNA base to mRNA base
CAT AGG GAG to...
GUA UCC CUC

Every gene's beginning starts with a Start Codon (AUG) and ends with a stop codon (UAA)

We then used this wheel to find the Amino Acid sequence based off of the mRNA sequence.

The Amino Acid sequence coded for a specific trait, and we used those traits to draw the Snoopy Snork. 

Explaining Pictures

Edgar Zwilling and John Saunders discovered two patches of tissues that controlled the development of bones inside limbs. One strip of tissue at the end of the limb bud is essential- without it the development stops. 

Mary Gasseling experimented with chicken eggs and took the patch of tissue from the pinky and put it on the first finger. The chicken resulted in having a new set of fingers that were mirror images of the normal set. The gene inside the tissue was able to control the development of the pattern of the fingers. (mirror image duplication)

The patch of tissue is the zone of polarizing activity (ZPA) How did it control the formation of fingers and toes? There is the concentration-dependent idea which explains that there is a high concentration of ZPA.

Denis Summerbell experimented with the idea and put foil between the ZPA patch and the rest of the limb. The foil was a barrier to prevent any molecule from diffusing to the other side. It resulted in cells on the ZPA side forming digits and the opposite side had barely formed digits. Something spread out of the ZPA that controlled how digits formed.

That something was the sonic hedgehog gene. It is what causes the ZPA tissue to do what it does. When things go wrong with sonic hedgehog, like in this picture, hands become messed up because the gene is not turned on properly during the 8th week of human development. 

Errors sometimes happen when the DNA is copied from the parent to the daughter cell. The error is called a mutation and it is not done randomly. Evolution favors a mutation that helps an organism discover adaptations to help it survive. So this flower's mutations were triggered by outside influences. McClintock discovered "jumping genes" (transposons) that proved that mutations are not just random. They remain in an active gene after inserted and make a difference. There are two different ties of jumping genes: DNA transposons which cut and paste, and Retrotransposons which copy and paste. This flower was affected by the DNA transposons where the code of the gene splits and it loses its trait which causes a change in the physical trait. 

11/4 DNA Replication Enzymes

Steps to replication-
1) Helicase- breaks hydrogen bonds "unzips"
2) RNA Primer- primes it with RNA nucleotides, reads 3-5, OH on 3
3) DNA Pol III- reads 3-5, adds nucleotides to synthesizing strand
4) DNA Pol I- Replaces RNA nucleotide with DNA nucleotide (new DNA)
5) DNA Ligase- Lagging strand has Okazaki fragments, ligase creates phosphodeister bond (bond between phosphate and sugar in nucleotide) and seals gaps

Reading Assessment: Chapter 3 Your Inner Fish

body made up of hundreds of cells

cellular diversity gives tissues and organs functions and distinct shapes

despite their differences, there is a similarity= exact DNA

-individual genes turning on and off inside each cell during development

makes protein that can affect how the cell behaves 

making hands

Edgar Zwilling and John Saunders

experiment on chicken eggs

-how the pattern of the skeleton forms

discovered: two patches of tissue control the development of the pattern of bones inside limbs

strip of tissue at end of limb bud is essential- without it, the development stops

Mary Gasseling

experiment on chicken egg

-took patch of tissue from pinky and put it on first finger

result: new fingers mirror images of normal set

-gene inside tissue able to control development of pattern of fingers

(mirror image duplication)

patch of tissue: zone of polarizing activity (ZPA)

-tissue that causes pinky side to be different from thumb side

-control formation of fingers and toes

how?

concentration-dependent idea- high concentration of ZPA

Denis Summerbell

foil between ZPA patch and rest of limb

-use barrier to prevent any molecule from diffusing to other side

results: cells on ZPA side formed digits

cells on opposite side barely formed digits (malformed)

something spread out of ZPA that controlled how digits formed (hedgehog gene)

the DNA recipe

one molecule started whole thing

fly experiment

-pattern of gene activity that makes body of fly from a single celled egg

hedgehog gene- made one end of body segment look different from the other

(similar to ZPA)

hedgehog gene has a specific DNA sequence

-scientists found sequence in other animals

animal version of gene= sonic hedgehog 

(mimics activity of ZPA)

active in ZPA tissue

vitamin A cause s.h to turn on in the opposite side of limb

-make fingers distinct from one another-depends on how close finger is to gene

-when things go wrong with sonic hedgehog- hands messed up

not turned on properly during 8th week of human development=extra fingers

giving sharks a hand

sharks: earliest creatures that have fins with skeleton inside

mermaid’s purses- skate embryo

(cartilage)

-apply same experiments as they did to chickens

sonic hedgehog’s role in its limb?: YES

similar effect to fin (duplicate)

experiment

a skate embryo with a bead inside that leaks mouse s.h protein

result: develop different from one anther (responded to gene, like chickens did)

-s.h does something similar in skates and in humans

-genetic recipe similar

recipe that builds our hands has deep roots in other creatures

“inner fish”- biological tools that build fins

-all appendages are built by similar genes

-connections among creatures