1. Already covered (Mendelian): “simple” dominance of 1 trait (10.3) “simple” dominance of multiple traits (10.4) Additional patterns of inheritance Linked genes (10.5) Incomplete Dominance (10.6) Codominance (10.6) Multiple alleles (10.6) Epistasis (10.6) X-linked and Y-linked (10.7) Mitochondrial/Maternal (supplemental) Pleiotropy (10.6) Multifactorial (10.9) Polygenic (10.9) Epigenetics (gene regulation- 7.6) Transposable elements (7.7) Patterns of inheritance

2.  Located on the same chromosome as one another  Inherited together ◦ law of independent assortment only applies to genes that AREN’T linked/NOT on the same chromosome as one another Gene map- Shows the relative location of each gene on the chromosome

3.  Genes on the same chromosome do not ALWAYS stay linked ◦ Crossing-over (occurs during Prophase I of meiosis) separates the genes ◦ Produces new combinations of alleles (genetic diversity) which will increase the likelihood of a species surviving ◦ Distance matters!  More distance = more likely to cross-over

4. b A A A a a a a A B B B B b b b

5.  when neither allele is completely dominant over the other  heterozygous phenotype is a blending of the trait ◦ My preference- A capital letter represents one of the incompletely dominant alleles. The same capital letter prime (P’) represents the other incompletely dominant allele.  Also acceptable - I’ve seen in other books &/or Keystone:  Two different capital letters  Same letter- capital and lower case 

6.  In snapdragons, red flower color (RR) is incompletely dominant to white (R’R’) flower color. A heterozygous snapdragon is pink (RR’). Cross a pink snapdragon with a pink snapdragon.  In humans, curly hair (HH) is incompletely dominant to straight hair (H’H’). The heterozygous individual has wavy hair (HH’). Cross a person with curly hair with a person who has wavy hair.

7.  when both alleles are dominant  heterozygous individual shows both alleles expressed equally ◦ My preference- A capital letter represents one of the codominant alleles. A different capital letter represents the other codominant allele so that the two do not get mixed up.  Also acceptable - I’ve seen in other books &/or Keystone:  Two different capital letters  Same letter- capital and lower case

8.  In chickens, black feather color (BB) is codominant to white feather color (WW). Both feather colors show up in a checkered pattern in the heterozygous individual (BW). Cross a checkered chicken with a checkered chicken.  In horses, gray horses (GG) are codominant to white horses (WW). The heterozygous horses (GW) is an appaloosa horse (a gray horse with white spots on the rump and loins). Cross a white horse with an appaloosa horse.

9.  when more than two different alleles exist for the same trait  Remember: each individual will only have two genes for a trait but there are several alleles possible. My preference

10.  In rabbits, coat color is controlled by multiple alleles. Dark-gray (C), white (c), light-gray or chinchilla (c ch ) and white with black points or a Himalayan (c h ). Chinchilla is dominant to Himalayan and white. Cross the following: Cc (dark-gray) X c ch c (chinchilla)  Cross a person that is heterozygous for type A blood with someone that is heterozygous for type B blood.  Cross a person with type AB blood with a person with type O blood.

11.  Condition in which 1 gene affects the expression of another gene  Example- Labrador retriever coat color ◦ Gene 1 (B/b)- coat color (black/brown) ◦ Gene 2 (E/e)- pigment expression (expression/no exp) ◦ Bbee  yellow; E/e is epistatic to B/b

12. Sex linked – genes are located on a sex chromosome - X (X-linked; many traits including more than 100 disorders) - Y (only a few traits)

13. Males have just one X chromosome thus all X- linked alleles are expressed in males, even if they are recessive! X-inactivation Only one X chromosome is active at a time Males: single X chromosome present is always active Females: one active X chromosome one barr body (turned off X chromosome)

15.  Egg/sperm- disproportionately sized ◦ Egg donates cytoplasm to zygote… therefore mitochondria comes from mom  If mom has mitochondrial disorder, ALL kids will have it too  If mom does NOT have mitochondrial disorder, none of the kids will have it (even if dad does)

18.  Trait has a genetic component that can be affected by the environment  Examples: ◦ Skin tone (UV causes tanning) ◦ Crocodiles (egg temperature determines gender)

19.  More than 1 gene controls the trait ◦ These genes can also then be affected by the environment  Creates a phenotype continuum  Examples: ◦ Skin tone (3 genes) ◦ Eye color ◦ Human height

20.  Subfield within genetics that focuses on gene regulation  Epigenome- set of which genes are on/off in an individual ◦ Explains why one identical twin can have a disease and the other can be healthy  PBS Epigenetics video clip PBS Epigenetics video clip

21.  Shortened- transposons  “Jumping genes” ◦ Pieces of genetic material can move ◦ Discovered by Barbara McClintock ◦ When transposable elements insert into a gene, they interrupt the expression of that gene  Corn  Purple = dominant  transposon interrupts purple gene = yellow  interrupt then jump out = spotted