sexual reproduction: the reproductive process that involves two parents who combine their genetic...

Sexual Reproduction:• The reproductive process that involves two parents who combine their genetic material to produce an offspring that is not identical to either parent.

• So, what are the important parts?

Sexual Reproduction:•The reproductive process that involves two parents who combine their genetic information to produce offspring that is not identical to either parent.

•What are some examples of organisms that are able to reproduce this way?

What is the advantage of having two parents?

Advantage of two parents:

• You get more genetic variation:

Which means…

Because half of the DNA comes from the female and half from the male…

You get a mix of traits—more variety!

How do you get so many differences in traits?

• Well, let’s start at the very beginning…a very good place to start!

• If you look at the DNA of any cell, you will find that each strand of DNA has a pair or partner.

How do you get so many differences in traits?

• Well, let’s start at the very beginning…a very good place to start.

• If you look at the DNA of any cell, you will find that each strand has a pair or partner.

• These are called homologous pairs• One of the chromosomes from a pair

comes from mom, and one comes from dad.

• They code for the same type of traits

• All organisms that reproduce sexually have the ability to make special cells called GAMETES.

• Gametes: special cells that only have half of the DNA that all the other cells have

• Gametes are AKA: sperm/egg cells

• How do gametes end up with only half of the DNA?

MEIOSIS:The making of GAMETE CELLS

Before we do this, let’s review

MITOSIS!

Remember PMAT?

Differences between MEIOSIS and MITOSIS:

Meiosis:•End up with four cells instead of two

– Four cells are called GAMETES

•Each gamete only has HALF the DNA•How does meiosis get four cells with half the DNA?•Goes through PMAT TWICE!!

Meiosis Video

• http://www.youtube.com/watch?v=D1_-mQS_FZ0#t=57

http://www.youtube.com/watch?v=D1_-mQS_FZ0#t=57

http://www.youtube.com/watch?v=D1_-mQS_FZ0#t=57

Gamete Fusion

• Gametes are AKA:

Gamete Fusion


• Gamete fusion:

Gamete Fusion


• Gamete fusion: when a sperm fuses with an egg

• Gamete fusion is AKA:

Gamete Fusion



• Gamete fusion is AKA: fertilization

• Zygote:

Gamete Fusion



• Gamete fusion is AKA: fertilization

• Zygote: sperm + egg cell = new “baby” cell

Gamete Fusion

________ Twins

Dominant vs. Recessive

Dominant trait:


Dominant trait: the stronger trait

- Use an uppercase letter

Ex: Free earlobe =



- Use an uppercase letter

Ex: Free earlobe = F

Recessive trait:



- use an uppercase letter


Recessive trait: the weaker trait

- use a lowercase letter

Ex: Attached earlobes =



- use an uppercase letter


Recessive trait: the weaker trait

- use a lowercase letter

Ex: Attached earlobes = f

Letter Dominant Number Letter Recessive Number

Free Earlobes Attached Earlobes



Farsightedness Normal Vision




Brown/Dark HairBlond, light, red hair





DimplesNo Dimples





Dimples No dimples

Widow Peak No Widows Peak





Dimples No dimples


Extra DigitsNormal Number

Digits





Dimples No dimples



Digits

Double-jointedness Normal joints





Dimples No dimples



Digits

Double-jointedness Normal joints

Normal blood clotting

Hemophilia


Genotype:


Genotype: genetic make-up of your cells, Represented by two letters

i.e. what your genes “say”

Homozygus:

Heterozygus:

Phenotype:


Genotype: what your GENES say

Homozygus: FF or ff

Heterozygus:

Phenotype: What you PHYSICALLY show



Homozygus: FF or ff

Heterozygus: Ff


Homologus pair of chromosomes:



Homozygus: FF or ff

Heterozygus: Ff


Homologus pair of chromosomes: one came from mom, one from dad

Ex: genotype: mom = dad =



Homozygus: FF or ff

Heterozygus: Ff



Ex: genotype: mom = dad =

phenotype: mom = dad =



Homozygus: FF or ff

Heterozygus: Ff



Ex: genotype: mom = FF dad = ff

phenotype: mom = Free dad = Attached



Homozygus: FF or ff

Heterozygus: Ff



Ex: genotype: mom = FF dad = ff

Punnett square or hybrid cross

Mom =

Dad =


Hidden trait:


Hidden trait: gene that someone has but doesn’t express

Carrier:


Hidden trait: trait that someone has but doesn’t show

Carrier: someone that carries a hidden trait, meaning they have a heterozygous genotype and the recessive gene will not be expressed or shown

Dihybrid cross• Curly hair and widow’s peak are

both dominant traits. If a mom was heterozygous for curly hair and homozygous recessive for widow’s peak. What is her genotype?

Dihybrid cross• What is the genotype of a

man who is homozygous dominant for curly hair and heterozygous for widow’s peak?

Dihybrid crossDad’s genotype:

Mom’s genotype::

Chromosome Pair #23

Gender:

Chromosome Pair #23

Gender: coded for by chromosome pair #23

Girl =

Boy =

Chromosome Pair #23


Girl = XX

Boy = Xy

Chromosome Pair #23


Girl = XX

Boy = Xy

X Linked Traits: Traits that are coded for on the 23rd chromosome

Anastasia

Romanov FamilyTzar Nicholas Romanov

(1868-1918)

MalesMales & & FemalesFemales have Different have Different Inheritance PatternsInheritance Patterns

– ALL of a male’s X-linked genes are expressed.

– Males have no second copies of X chromosome

– Because of this, males can NEVER be “carriers” of X-linked traits or disorders.

– Ex: Colorblindness, Hemophilia, Muscular dystrophy

67

More punnett square practice

More punnett square practice

• Will baby Lyla be color blind?

• Lets do a punnett square and see

Pedigree Charts (How to interpret)

Girl = Boy =

Married = line between circle and square

Divorced = ----- dashed line between circle and square

Children = vertical line down from parents

Adopted = ---- dashed vertical line from parents

Has trait = filled in

Carries trait= half filled in

Pedigree Charts

• Go back to the dominant vs. recessive chart. Pick on trait and make a list of all your family members and write by their name whether they have the dominant trait or the recessive trait.

• Remember: Blond and Red hair are recessive traits, brown is dominant

• Blue/green eyes are recessive, brown eyes are dominant

Make your own

• Make a pedigree chart of your family using the dominant/recessive traits of your family you just listed

• Be sure to label each individual of your family

• Include as many extended family members as possible

• List the GENOTYPES of each individual

Mammals

Amphibians, Reptiles, and Fish

Insects

http://www.thais.it/entomologia/Mix/mix.htm

http://www.thais.it/entomologia/coleotteri/particolari/s00043_uk.htm

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