{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture 6 Outline - Expressivity the degree to which a...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Bio 352 1 of 4 LECTURE 6 : Modifications to Mendelian Patterns Today’s topics: 1. Dominance 2. Penetrance 3. Multiple alleles 4. Gene interactions. Readings : Pierce, pgs. 99 – 117; 119 - 120 In Lecture 6 we are going to investigate patterns of inheritance vary from those predicted by Mendel’s 1 st and 2 nd Laws – these laws hold for many cases, but they are not sufficient to explain ALL patterns of inheritance. Dominance : heterozygote has the same phenotype as one of the homozygotes. Incomplete dominance – heterozygote phenotype is intermediate between the 2 homozygote phenotypes -- Figure 5.2 Codominance : heterozygote simultaneously expresses the phenotypes of both homozygotes -- heterozygote is not intermediate between homozygotes. Summary: Table 5.1 . Penetrance : % of individuals having a particular genotype that express the expected phenotype.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Expressivity : the degree to which a character is expressed. Example Polydactyly in humans – Figure 5.3 Bio 352 2 of 4 Multiple alleles . Feather pattern in mallard ducks -- Figure 5.4 . ABO blood types Figure 5.5 . Gene interaction . Example : fruit color in the pepper, Capsicum annuum – Figure 5.6 . Epistasis – results in deviation from the normal 9:3:3:1 phenotypic ratio. The epistatic and the hypostatic gene. Bio 352 3 of 4 Recessive epistasis Example: coat color in Labrador Dominant epistasis . Example: Summer squash -- Figure 5.9 . Sex-influenced traits – Figure 5.12 Bio 352 4 of 4 Sex-limited trait-- Figure 5.14 Cytoplasmic inheritance Genetic maternal effect – Limnaea peregra ( Figure 5.17) Next Time : Pedigree Analysis (Lecture 7) Readings : Pierce, pgs. 134 - 142...
View Full Document

{[ snackBarMessage ]}