Knudsen's 2-Hit Hypothesis

Autosomally inherited cancer risk.

Hereditary Colorectal Cancer CRC

Tumor suppressor mutation - dominantly inherited risk for CRC.

APC gene involved in mismatch repair.

Retino-Blastoma

Autosomally dominant tumor suppressor mutation.

Newborn Screening

Newborns are screened for genetic disorders

Identifies inborn errors in metabolism.

Sex Determinism

Environmentally Determined Sex

Reptiles mostly use incubation temperature.

Sea turtles.

Genic Sex Determinism

Uses pheromone genes do change gender expression.

Baker's Yeast

Haploidiploidy

Insects - if fertilized egg then diploid = female.

If no fertilization then haploid and male.

Monotremes

Platypus has 10 sex chromosomes.

Birds

Use ZW sex chromosomes.

Male = ZZ

Female = ZW

Drosphila Melanogaster

Genic balance ratio

Ratio of X chromosomes to ploidy (haploid = 1, diploid = 2, triploid = 3).

Not whether the Y chromosome exists or not.

When doing phenotype calculations, you need to account into account the ratio of sex/gender in the offspring.