BIOL 112 Lecture Notes - Lecture 15: Coin Flipping, Ploidy, Inbreeding
15 Jun 2018
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BIOL 112: MEDELIAN GENETICS I
- Ploid: prole is ot the sets of hroosoes, it’s the ratio of hoologs
- Odd: Trisomy: 1:1:1.5 & Triploid 1:1:1
- Even: Tetraploid 1:1:1 & Diploid 1:1:1
o Multiple ploidy ([more ploidy you have], the bigger you tend to be
o E.g. farmers mate different ploidies to make bigger fruits → messed up ratios
Genetics: why do we resemble our parents (heredity)?
- Characters: features (colour, height, facial)
- Traits: offspring share traits but do not have identical traits but share character, (light/dark,
stature)
Types of Variation:
- Continuous Variation: for skin colour, height, hair, continual spectrum of these features and
most of what we pay attention to
o Inheritance: features blend, e.g. mixed-race parents → children skin colour is blended
- Discrete Variation: discrete traits (e.g. fur colour in mice where there are only 3 fur colours you
get)
o Medel’s Peas: peas produe lots disrete traits
o Two true breeding strains; made sure they were inbred that when you cross them they
gave the same traits as their parents
Medel’s Eperiet:
o Wrinkled & Round peas: count the peas, collect the data, cross them, they all bred
round pea (dominant), then took the product of the first cross (F1) crossed them then
wrinkled came back (recessive) in a ratio of 3:1
o Ratio is 3:1 for general traits of dominance
o Not all-round peas are equal; some are high in the wrinkled trait, then when you cross
them with a wrinkled pea get some wrinkled progeny
▪ Hides in a specific ratio
o Parental Generation: 1 round (SS) 1 wrinkled (ss) → 4 Ss
o F2 generation: 2 rounds (2x Ss) → 1 ss (3:1)
Heredity: exists in discrete units that travel through time
Genetics Terms:
- Unit of heredity = gene
- Different gene flavours = alleles
- 2 same alleles = homozygous
- 2 different alleles = heterozygous
o Probability of getting each type of progeny (e.g. like coins) the probability of 2
independent evets is the product of the probability of each event
e.g. coin flipping explaines sibling alleles
find more resources at oneclass.com
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Document Summary
Ploid(cid:455): pro(cid:271)le(cid:373) is (cid:374)ot the sets of (cid:272)hro(cid:373)oso(cid:373)es, it"s the ratio of ho(cid:373)ologs. Even: tetraploid 1:1:1 & diploid 1:1:1: multiple ploidy ([more ploidy you have], the bigger you tend to be, e. g. farmers mate different ploidies to make bigger fruits messed up ratios. Traits: offspring share traits but do not have identical traits but share character, (light/dark, stature) Continuous variation: for skin colour, height, hair, continual spectrum of these features and most of what we pay attention to. Inheritance: features blend, e. g. mixed-race parents children skin colour is blended. Heredity: exists in discrete units that travel through time. 2 different alleles = heterozygous: probability of getting each type of progeny (e. g. like coins) the probability of 2 independent evets is the product of the probability of each event e. g. coin flipping explaines sibling alleles. Genotype: the set of alleles an organism has, you can determine the phenotype from this.
