Day 1 Guided NotesWhat is Genetic Counseling?

A service for couples with a risk of having a child with a certain disease

The counselor will:

Take a family ______________.

Construct a _________________.

Determine type of ________________.

Suggest and arrange for testing.

Provide support.

Types of Prenatal Test

Karyotype – shows abnormalities in ____________________

o Cells in metaphase –

used to see visible chromosomes

chromosomes are arranged in ordered pairs

o Shows extra or missing chromosomes

Sampling of ___________________ material

o Amniocentesis (fluid surrounding the fetus)

Done at 14-18 weeks

o Chorionic villus sampling (outer tissue)

Can be performed at 8 weeks

Maternal serum screening – test of blood for levels of certain substances or _________ analysis

Ultrasound (visual image)

Family exome analysis

o order of DNA bases

o uses DNA that codes for proteins

o searches for mutations in family members

Biotechnology and Genetic Testing

Use of biotechnology tools to analyze _______________

Diagnostic tools:

o DNA _____________________________

shows unique individual ____________ in DNA

also used for crime scene detection

o ___________ (polymerase chain reaction)

produces large amounts of DNA from a small sample

o Restriction Enzymes “DNA scissors”

___________ DNA strands in the same _______________ to create DNA

fragments

o DNA fingerprinting and Gel Electrophoresis

DNA samples are cut with the same restriction enzymes to create DNA fragments

Gel electrophoresis is used to _______________ DNA fragments by __________

to show fragment length.

Electrical current pulls DNA fragments through the gel

Each sample is loaded into the gel for comparison to known DNA.

Treatment options:

o Gene _______________

using an inactive virus to replace a defective gene

o Gene _________________

produces large amounts of compounds for treatment (ex., cloned insulin for

diabetes patients)

o Pharmacogenetics

determining drug treatment choice and dosage based in individual DNA

Day 2 Guided NotesGenetics Gregor Mendel:

is considered the “Father of Genetics”o Genetics – the study of heredity and the _________________ of inherited characteristics.

studied inheritance of traits in pea plants. developed laws of __________________. disproved the blended inheritance theory – states genetic material of offspring is a uniform blend

of the parents’ genetic material.Understanding Genetics

One conclusion that Mendel reached was the idea that you cannot only use external/physical resemblances to form conclusions as to an organism’s internal/genetic make-up. Scientists now use ____enotype to refer to refer to the external or ____ysical characteristics of

an organism. The word ____notype is now used to refer to the

internal or ____netic makeup of an organism.So what are these letters? Each parent passes one copy of each trait to their

offspring. Each gene can exists in different forms, called _______________. Each letter represents an allele.

What is the difference between upper case “allele” and a lower case “allele”? The upper case letter represents a _______________ allele. The lower case letter represents a _______________ allele.

Understanding Genetics – Alleles

Each parent has 2 ________________ for each trait. The two alleles separate when a gamete forms. This describes Mendel’s Law of Segregation.

There are ____ different combinations of alleles that an offspring can receive from their parents

Understanding Genetics – 3 allele combination

SS – this offspring has received 2 _______________ alleles from its parents. This offspring is referred to as __________________ dominant (pure dominant/purebred dominant).

Ss – this offspring has received 1 dominant and 1 recessive allele from its parents. This offspring is referred to as heterozygous (hybrid).

o Mendel’s __________ __ ________________ states that when a dominant allele and a recessive allele are present in a organisms genotype, the dominant allele will mask the recessive allele in the phenotype.

ss – this offspring has received 2 _______________ alleles from its parents. This offspring is referred to as _______________ recessive (pure recessive/ purebred recessive).

Based on what you know about allele combinations, describe the genotype of each pair of homologous chromosomes to the left. P.S. - use appropriate scientific terminology, always!

Genetic Counseling – determining possible genetic outcomes?

Punnett squaresLet’s look at a monohybrid cross. We are working with pea plants like Mendel. We are going to cross a homozygous dominant white flower and homozygous recessive violet flower. What are the possible genotypes and of the offspring?

We will use W for the dominant allele (white color) and w for the recessive allele (violet color). Identify the alleles that make up the genotype of each parent.

o Plant 1 = WW, Plant 2 = ww Then separate and distribute them along the top and left side of the square. (Law of Segregation) Complete the cross by placing two alleles in each box based on the outsides of the box. What are the possible genotypes?

What are the possible phenotypes?

Genetic Counseling – analyzing inheritance of genetic traits - Pedigrees

Pedigrees are family trees which show the parents and offspring across generations, as well as who

possessed particular traits.

Genetic counselors use pedigrees to aid them in providing information to families who may be at risk

for various genetic conditions.

The diagram to the left is an autosomal

___________________ pedigree.

A key characteristic of this pedigree is the trait being seen

at _______________ generation.

Each row represents a new generation.

In generation 1, what is the genotype of the father?

The diagram below is an autosomal recessive

pedigree.

Key characteristic - the recessive trait ______ being seen in every generationWhy?

Remember - dominant traits only require one dominant allele for expressionEach row represents a new generation.Sometimes generation 1 is referred to as the P

generation.Sometimes generation 2 is referred to as the F1 generation.In generation 1, what is the genotype of the father?

Day 3 Guided Notes

Genetics During the last class, we talked about Gregor Mendel and his work with pea plants. He:

studied inheritance of traits in pea plants, and

developed laws of inheritance.

We also worked with monohybrid crosses -

the possible genetic outcome of _________ trait

We are also able to determine possible genetic combinations of two traits at a time,

a __________________ ____________________.

Understanding Genetics – Alleles

What is the difference between a dominant allele and a recessive allele?

Name and describe the 3 combinations of alleles.

How many alleles does each parent have for each trait?

Explain and give an example of the Law of Segregation.

Based on what you know about allele combinations, determine and describe the genotype of this

organism for both traits.

P.S. - use appropriate scientific terminology, always!

Mendel’s Law of independent assortment

Mendel’s Law of independent assortment - alleles of two (or more) different genes get sorted into gametes __________________________ of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.

Let’s take our organism from the previous slide, genotype BbRr. What are the possible allele combinations to be passed on for each trait independently?We use the FOIL method to determine allele combinations for gametes. refers to the position of the alleles in the 4 lettered genotype (for our example, BbRr).

First, (refers to the first allele in each pair of traits.) Outer, (refers to the first allele in the first pair and the last allele in the second pair) Inner, (refers to the last allele in the first pair and the first allele in the second pair) Last, (refers to the last allele in each pair)

Genotype = BbRr Combinations: 1. 2. 3. 4.

Determining possible genetic

Punnett squaresLet’s look at a dihybrid cross. In a dihybrid cross, we determine the possibilities of genetic outcome of two traits at one time.

outcomes with multiple traits

We are going to cross two organisms who are heterozygous for both eye color and handedness. What are the genotypes of the parents? What are the genotypes of the parents?

We will use B for the brown eyes and b for blue eyes. We will also use R for right handed and r for left handed.

Identify the alleles that make up the genotype of each parent.o Parent 1 and Parent 2 = BbRr

Then determine all possible allele combinations for the parents to pass on. (Independent Assortment) (FOIL method)

o BR, Br, bR, br, for both parents Then distribute them along the top and left side of the square. Complete the cross by placing four alleles in each box based on the outsides of the box. Keep

like alleles together and capital letters first

What are the possible genotypes?

What are the possible phenotypes?

Day 4 Guided NotesUnderstandin Describe the 3 allele combinations that we have discussed so far.

g Genetics – Non-Mendelian Inheritance

A few classed ago we covered Mendel’s Law of Dominance. o Which of the three allele combinations does it apply to? Explain.

There are other types of inheritance patterns of inheritance (Non-Mendelian).o Gregor Mendel and his work with pea plants. He:

Studied inheritance of traits in pea plants. Developed laws of inheritance. Disproved the theory of blended inheritance.

However, the phenotype of a heterozygous organism can be a blend of phenotypes of its homozygous parents .

Today we are going to cover blended inheritances; incomplete dominance, codominance, and polygenic inheritance.

Incomplete Dominance

Incomplete dominance is expressed when a heterozygous phenotype exhibits a _________________ of

the two alleles it possesses.

Neither allele has complete dominance over the other, which results in a _____________ phenotype.

The most common example of type of inheritance is a snapdragon flower.

A red colored flower = _________ (C=color, R=red), is crossed with a white colored flower =

__________ (C=color, W=white).

Use Mendel's Laws of segregation and independent assortment to identify the gametes and complete

the Punnett square.

What are the possible genotypes and phenotypes of the offspring?

Incomplete Dominance

Pedigrees are family trees which show the parents and offspring across generations, as well as who

possessed particular traits.

So far, we have only looked at pedigrees that have completely filled in shapes for organisms that exhibit

a trait, and empty shapes for organisms that do not exhibit a trait.

Pedigrees can also show more detailed information.

A _____________ shape shows a heterozygote.

If the pedigree to the left represents snapdragons, what are the phenotypes of the offspring in the

F1 generation?

●Red

○ White

Codominance Codominance is expressed as a _________________________ phenotype with both alleles being displayed at the same time. Neither allele has dominance over the other, but are not blended and are both ____________ and ____________________ expressed, which results in a third phenotype.A common example of codominance is a camellia flower A red colored flower (RR) is crossed with a white colored flower (WW).

Use Mendel's laws of segregation and independent assortment to complete the Punnett square.

What are the possible genotypes and phenotypes of the offspring?

Codominance Pedigree

The pedigree below analyzes the family genetics of two organisms that mate, and it shows the genetic information from each organism.

If the pedigree to the left represents camellia color (codominance), what are the phenotypes of the parents of the organisms that mated?

●Red

○ White

Polygenic Inheritance

Polygenic inheritance is expressed when ___________________ genes each make a small

contribution to the overall phenotype.

Allows for more than 2 or 3 variations in expressed ___________________

o For example, skin color ranges from very fair to very dark skin shades.

o At least 378 genes are involved in determining skin color.

o Another example - 7 genes are involved in determining fingerprints.

Environment can contribute to the polygenic phenotype (known as multifactorial inheritance).

Punnett squares are complicated for polygenic inheritance.

Data can be gathered to determine a polygenic inheritance pattern.

Day 5Guided NotesSex linked Traits Sex linked traits are associated with genes found on ____________ chromosomes.

What are the human sex chromosomes? Which two do males possess? Which two do females possess?

The X chromosome is larger than the Y, therefore X-linked traits are more common than Y-linked traits. An example of an X-linked trait is __________________ in humans. Hemophilia is an X-linked recessive disorder, and is a condition in which the blood does not clot normally.A heterozygous female is crossed with a male with hemophilia.What are the possible genotypes and phenotypes of the offspring?

What are the possible genotypes and phenotypes of the offspring of a male without hemophilia and a female carrier of hemophilia

Sex linked traits pedigree

The diagram below is a sex linked recessive pedigree. A key characteristic of this type of pedigree is that males are exclusively or _________ ___________ to be affected than females. Also, X-linked traits _________ be passed from father to son.

Females rarely show signs of X-linked recessive conditions as they usually have a second unaltered copy of the gene on their other X chromosome to compensate for an altered gene.Remember - each row represents a new generation.

In generation 1, what is the genotype of the mother and father? How do you know?

Multiple alleles Multiple alleles occurs when there are _________ or ___________ forms of a gene, allele, for a

trait. Only two of the alleles will be expressed as the phenotype. Multiple alleles allows for many possible dominance relationships resulting in a ________________

of genotypes and phenotypes. In humans a common is example is blood types where three alleles can determine blood type: A, B,

and O

A (IA) and B (IB) are both ___________________ (codominant to each other) O (i) is recessiveThe i in each blood type stands isoagglutinogen, another term for antigen.There is a specific antigen for each blood type which allows us to test for blood typeIf a heterozygous type A and a heterozygous type B mate, what are the possible genotypes and phenotypes of the offspring?

What are the possible phenotypes of the offspring if one homozygous recessive and one heterozygous codominant mate?

Day 6Guided NotesEthics and Biotechnology

Manipulating DNA using biotechnology methods can have ethical consequences on the

_______________, society and the ________________.

Biotechnology applications include work in the fields of medicine and agriculture.

Genotype(s) Phenotypeii OO O

IAIA, IAi AA, AO AIBIB, IBi BB, BO B

IAIB AB  AB

Ethics: moral principles that govern a person's behavior or the conducting of an activity.

What are reasonable ethical limits for you?

Where are you willing to draw the line?

Yes (Y) Or No (N)

If biotechnology could assist with the following, how far would you be willing to go to prevent a child from being born with: 1.

2.

3.

4.

5.

6.

Y or N Would you be willing to:

1.

2.

3.

4.

5.

Y or N If biotechnology could solve a problem with society, would you be willing to: 1.

2.

3.

4.

5.

6.