Download Heredity Unit Notes (1)

(1) WHERE DO OUR LOOKS COME FROM?
• REMEMBER:
• Proteins are the expression of our genetic code.
• Our DNA stores our genetic code within the nitrogenous bases.
• The unique sequence of these nitrogenous bases = unique proteins =
unique traits
• We can also call a specific sequence of DNA a “Gene”.
(2) GENOTYPE & PHENOTYPE
• Genotype = The specific genetic sequence an organism has for a trait.
• Phenotype = The physical description of what an organism’s trait looks
like.
(3) WHERE DO OUR TRAITS COME FROM?
• We inherit our traits from our parents.
• Many animals, like humans, reproduce through “Sexual Reproduction”.
• Sexual Reproduction involves:
• The combination of a sperm cell and an egg cell (this is called fertilization).
• The division and growth of that single cell into trillions of specialized cells
(making a multicellular organism).
• Producing offspring that inherit ½ their genes from a male, and ½ from a
female.
SO WHAT HAVE WE LEARNED/DONE SO FAR?
• TRYING TO BREED A SUPER RARE GECKO, CHOOSING
2 CECKOS TO BREED.
• NEED TO UNDERSTAND GECKO GENETICS TO DO THIS.
• LOOKED AT DEJA AND ERIC’S GECKO BREEDING
RESULTS.
• LOOKED AT PCR CHARTS OF GECKO BREEDING
RESULTS.
• CAME UP WITH SOME RULES WE NOW KNOW ABOUT
GENETICS.
(4) VARIATION IN TRAITS
• “Different Types of Traits” = Different nitrogenous base sequences for a gene.
• Sexual Reproduction increases genetic variations and diversity in a population.
• Sex Cells are produced through a special type of cell division called “Meiosis”.
• In Meiosis, these different types of traits are mixed up and randomly assorted so
that each sperm and egg cell is genetically different from every other one.
(5) WHAT HAPPENS IN MEIOSIS?
• Meiosis is only used to make more sex cells.
• The amount of genetic information is cut in ½.
(So that when a sperm + egg combine, they will form a full set of DNA.)
• A special process called “Crossing Over” swaps random genes between
chromosomes, increasing genetic variation.
• Different types of genes (called “Alleles”) separate randomly of one another, also
increasing genetic variation.
(6) TYPES OF TRAITS
• All organisms inherit at least 2 alleles per trait or gene.
• One allele comes from the mother, one from the father.
• There are 2 main types of traits:
• Dominant = Traits which always show up.
(Represented by Capital Letters.)
• Recessive = Traits which only show up when 2 are inherited together.
(Represented by Lower Case Letters.)