Genetics

Flower dissection

Quiz 1. What is the name of the

male reproductive part of a flower? (Name ALL if there are more than one)

2. What is the name of the female reproductive part of a flower? (name ALL if there are more than one)

3. WHERE on the flower is the pollen?

4. How is a new flower produced? (meaning how does pollination happen?)

5. Identify structure A, B, C and D and write their FUNCTION.

AB

CD

Brainpop Video

Mendel

F1 and F2 Generation Practice:

#1: What would the F1 generation look like if a plant with round seeds was cross pollinated with a plant with wrinkled seeds?#2: What would the F2 generation look like if the results form above were self pollinated?#3: What would the F1 generation look like if a plant with tall stems was cross pollinated with a plant with short stems?#4: What would the F2 generation look like if the results form above were self pollinated?

Dominant RecessiveRound seed Wrinkled seedPurple color White colorTall stem Short stem

Allele for

Purple flowers

Allele for

White flowers

law of segregation - there are two factors controlling a given characteristic, one of which dominates the other, and these factors separate and go to different gametes when a parent reproduces.

Independent assortment - factors controlling different characteristics are inherited independently of each other.

Mendel’s Two Laws:

Mini LessonGenotype Phenotype

Explanation The ALLELES the individual inherits from parents

The EXPRESSIN of the genotype (what it looks like)

Example 1 PP Purple FlowersExample 2 Pp Purple FlowersExample 3 ll Short stemsExample 4 Ll Long stemsExample 5 Rr Round seeds

Homo = same Hetero = differentWhich of the examples above are homozygous? Which are heterozygous?

ProbabilitySperms

Eggs

Punnett SquaresPractice:

#1. Homozygote dominant crossed with a heterozygote

#2. Homozygous recessive crossed with a homozygous dominant

#3. Heterozygote crossed with a heterozygote

Incomplete dominance

Codominance

Polygenic inheritance

• Skin color

• Eye color

• Height

Pleiotropy

Pleiotropic versus polygenic

Autosomal traits Autosomal traits are controlled

by genes on one of the 22 human autosomes

 Examples: The allele for free-hanging

earlobes (F) is dominant to the allele for attached earlobes (f).

widow’s peak is dominant over no widows peak

Rolling your tongue is dominant over not being able to.

Sex Linked Traits Traits controlled by genes on the sex

chromosomes  X-linked traits in the case of the X

chromosome. X-linked traits have a different pattern of

inheritance than autosomal traits because: males have just one X chromosome. always inherit their X chromosome from

their mother they pass it on to all their daughters but

none of their sons

Autosomal Genetic Disorders

caused by mutations in one or a few genes on an autosome (chromosome #s 1-22)

If it is on an autosome, it can either be a “dominant disorder” or a “recessive disorder”

If it is a dominant disorder you will express the disorder if you are heterozygous for the trait or homozygous dominant.

If it is a recessive disorder you will only express the disorder if you are homozygous recessive for the trait.

AA/Aa

aa

Sex-Linked Genetic disorders

Disorders that are a result of 1 or more genes on a sex chromosomes (usually the x)

X LINKED RECESSIVE DISORDERS (most common): If a male carries 1 mutated copy of the gene he

will have the disorder. A female needs 2 mutated copies of the disorder

to have the disorder. If a female has 1 mutated copy she is called a

“carrier”, meaning she does not have the disorder but can pass it on to her offspring.

Chromosomal Genetic Disorders

Caused by an abnormal number of chromosomes

Mistakes may occur during meiosis that result in nondisjunction. This is the failure of replicated

chromosomes to separate during meiosis.

Some of the resulting gametes will be missing a chromosome, while others will have an extra copy of the chromosome

Examples of chromosomal

disorders

Autosomal Genetic Disorders

Sex Linked Genetic Disorders

Pedigrees A pedigree is a

representation that shows the blood relationships of family members

It shows individuals expressing the trait or disorder under study.

The chart describes relationship to various members of the family

It can also show the origin of a particular trait or disorder.

Inheritance patterns

Treating genetic diseases

• Just treat symptoms (PKU, cystic fibrosis, insulin for symptom prevention)• Gene therapy: replacing the

defective gene• Somatic cell gene therapy• Germ cell gene therapy

(controversial)

Genetic counseling

Pedigree Rules

Pedigrees

Layer B1. Mendel Photobook/scrapbook 3. Blood Typing Webquest: http://www.nobelprize.org/educational/medicine/bloodtypinggame/game/index.html2. Blood Type Mystery4. Punnett Square practice packetExtra Credit: Biotechnology brochure (processes, uses) As a class:

Baby lab Article jigsaw Gattaca

Layer A Genetic Counselor Project