Intro to Genetics

Homunculus Theory

The sperm contains a perfectly formed miniature human, whose growth is initiated upon implantation into the uterus

Ovist Theory

The egg cell contains a perfectly formed miniature human, whose growth is stimulated by the semen

Epigenesis

William Harvey- Substances within the embryo differentiate into body tissues, rather than body tissues being preformed

Germ Plasm Theory

August Weissman proposed that ovaries and testes each contain full sets of genetic information and that sperm and egg cells carry the information brought together in fertilization

Cell Theory

1. All life is made of cells

2. All cells come from other cells

Spontaneous Generation

Life will arise de novo from non-living substances

Fixity of the Species

Aligning with the idea of special creation: all species have not changed since they were formed

Blending Inheritance

The offspring will tend to have trait values near the average of the parents

Fleeming Jenkin

Stated that adaptive evolution is not compatible with blending inheritance b/c it does not matter how advantageous a new variant is, it will tend to be diluted out each generation

Mitosis

Replication and equal division of chromosomes into two daughter cells (Both 2N)

Meiosis

Two rounds of division yielding 4 haploid gametes

Haploid

Having only one copy of gene in the genome

Gametes

Reproductive cells (eggs and sperm)

Universality of Mendelian Inheritance

All traits are fundamentally inherited according to the rules of Mendelian inheritance

Structure of DNA

Nucleotides have 3 components:

• Phosphate

• Ribose/deoxyribose sugar

• Nitrogenous base

• Joined into polymers via covalent phosphodiester bonds

DNA exists as a complementary, antiparallel, duplex that is held together via hydrogen bonds

• Translated into RNA

RNA

• Has ribose instead of deoxyribose

• Has uracil instead of thymine

• Single-stranded

• Can form complementary structures with DNA

• Translated into proteins

tRNA

The molecule that translates DNA/RNA into protein using the genetic code

William Harvey

Credited with the first explanation of epigenetics

LUCA

Last Universal Common Ancestor

Gregor Mendel

Pea plant heredity

August Weissman

Germ plasm theory

Edmund Beecher Wilson

proposes that “nuclein” is the hereditary material, and that “inheritance may, perhaps, be affected by the physical transmission of a particular chemical compound from parent to offspring

Archibald Garrod

Black urine disease, autosomal recessive- defective in the breakdown of HGA