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?