Genetics & Prenatal Development
Ge Chromosomes – store and transmit genetic information.
DNA – substance of which genes and chromosomes are made.
Genes – segments of DNA located along the chromosomes.
Chromosomes, Cells, and Sex: Terms
Autosomes The 22 pairs of chromosomes that are not sex
• 23rd pair of chromosomes
• Determine sex
• XX = female, XY = male
Gametes / Sperm and ova
Zygote Sperm and ovum united
or fertilized ova
One zygote that divides
into two individuals
Forms of the same gene on a pair of chromosomes:
o Appear at the same place on each chromosome in the pair
o One allele is inherited from each parent Principles of Heredity
Mendel argued that certain traits are transmitted from parents to child
o Each trait is governed by two elements with one from each parent
o Phenotype refers to the expressed trait
o Genotype refers to the underlying genes that govern the trait
Dominant Vs. Recessive Traits
o Brown eyes
o Dark hair
o Blue or green eyes
o Blond hair
o No freckles
o No dimples
Are Men Obsolete?
Parthenogenesis: “virgin birth”, reproductio