WHAT CREATED YOU AT THE VERY BEGINNING?

Heredity & Environment

What are genes?

DNA (deoxyribonucleic acid) The basis of heredity Humans = 46 (23 pairs) of chromosomes Chromosome

Molecule of DNA Make up chromosomes

Genes = Section of chromosomes Allele = Slight normal variation in a gene

DNA GenesChromosomesIn cell nucleus

What is the code for making an individual?

Genome = The full set of genes for a specific organism (entire genetic inheritance)

20,000 genes (99% in other creatures also)Phenotype

What you look like based on your genes Appearance, personality, intelligence

Genotype = Hidden in your genes (e.g. Cancer)

Phenotype = Observable characteristics based on genes – E.g. brown eyes

Do you remember?

You have how many pairs of chromosomes?Your chromosomes are made up of what type

of molecule?What is the genome for a human?What is the difference between your

genotype and phenotype?

How does life begin?

What are gamete?

Sperm

Ovum (egg)

Each has 23 chromosomes (one half of 46)

What happens after fertilization?

A zygote developsSingle cell from two gametesThe first stage of development after

fertilization of the egg (ovum).

Male or female?

23rd pair of chromosomesFemale = XXMale = XY

What creates twins?

Monozygotic (identical) twins From one zygote

(One egg & sperm) Share 100% genes

Dizygotic (fraternal) twins Two sperm penetrating two ova

Share 50% of their genes

Do you remember?

After an egg is fertilized, it is called what?The 23rd. Pair of chromosomes in women are:The 23rd. Pair of chromosomes in men are:What is the monozygotic and dizygotic twins?

How can we help fertilization occur?

ART = Assisted Reproduction TechnologyIVF = In Vitro Fertilization

Sperm mixed with ova in glass dish Viable embryos implanted

ICSI (Intracytoplasmic sperm injection)

Intrafallopian sperm injection

From one cell to many:

How do genes affect appearance and behavior?

Genes + Environment = Phenotype (Appearance & behavior)

E.g. Alcoholism Genes(Varies in intensity) + Environment (Encourages

or discourages drinking) = ResultLarge breasts and shyness

If something is epigenetic, what is it?

Characteristics that are determined by both genes and environment E.g. height and nutrition

Additive heredity

Some alleles (gene variations) combine to affect appearance and behavior

Are some genes more powerful than others?

Dominant – recessive heredityDominate genes are more influential than

recessive genes.E.g. Brown eyes (Mother-dominate) + Blue

eyes (Father-recessive) = Brown eyed childBeing a carrier for blue eyes can effect this

What can cause genetic abnormalities?

Most often related to age of motherE.g.: Extra chromosome

E.g. Down Syndrome = 47 chromosomes

Abnormalities of the 23rd. Pair

Humans have 44 chromosomes + one X + an “X” or ”Y” Embryos do not develop without one X

Missing chromosome E.g. XO = Turner’s syndrome (looks female)

Three sex chromosomes XXY = Klienfelters Syndrome (Looks male) XYY = “XYY” Syndrome (looks male) Appear normal until puberty

What is the effect of genetic counseling?

Find harmful conditionsAffect insurance coverageJeopardize the marriage

Do you remember?

What are some methods of assisted reproduction?

How do genes and the environment interact?How do dominate and recessive genes control

who you became?What is the most common cause of genetic

abnormalities?What are some abnormalities of the sex

chromosomes?What are some of the positive and negative

effects of genetic counseling?