1 / 17

Incomplete & Codominance

Incomplete & Codominance. Reviewing. All photos from: http://www.naturalselectionreptiles.com/Genetics.html. Incomplete Dominance. (a.k.a. partial dominance or blending)  occurs when both alleles contribute to a trait that is not like either parent. 

uzuri
Download Presentation

Incomplete & Codominance

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Incomplete & Codominance

  2. Reviewing All photos from: http://www.naturalselectionreptiles.com/Genetics.html

  3. Incomplete Dominance • (a.k.a. partial dominance or blending)  • occurs when both alleles contribute to a trait that is not like either parent.  • this condition is only seen in the heterozygous individual  • ex.. Snap Dragons or Four O’Clocks or Morning Glory or Primrose (Flowers) • Curly (homozygous) or straight (homozygous), but if you are heterozygous you have wavy hair.

  4. Example: Snap Dragons CR= red  CW=  white   Parents are both true breeding red and white. Parents: Red  X  White CRCRX CWCW Genotype: All CRCW Phenotype: All Pink http://www.usask.ca/biology/genetics/extensions/snapdragon.jpg

  5. http://www.visionlearning.com/library/modules/mid129/Image/VLObject-3228-050216120240.jpghttp://www.visionlearning.com/library/modules/mid129/Image/VLObject-3228-050216120240.jpg F1 x F1 Cross CRCWX CRCW Remember: CR = red  CW =  white  Genotypic Ratio: 1CRCR: 2 CRCW: 1 CWCW Phenotypic ratio: 1 Red: 2 Pink: 1 White ***NOTE:  Because there is no dominance in the heterozygote the phenotypic ratio is identical to the genotypic ratio**** 

  6. http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial5_files/figure_14_9.gifhttp://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial5_files/figure_14_9.gif http://library.thinkquest.org/20465/media/flowers.gif

  7. How the coloring works . . . • CRCR = have enough pigment to be red. • CWCW =flowers don’t have any pigment. = no color • CRCW = only have enough pigment to be pink.

  8. Codominance • the two dominant genes are expressed at the same time  • both traits appear in the heterozygous individual at the same time • ex.. Roan (Red or Blue) coat color in horses and cattle  • Chestnut and White color in horses are both dominant traits; the heterozygous individual is a palomino (golden).

  9. Red Roan Example: http://www.naturalselectionreptiles.com/Genetics/exCodominance.jpg

  10. Red Roan Example: http://www.brokenlfarm.com/images/sale/kbrowdypetejr/102_8424.JPG Blue Roan Example: http://www.virginiacowboy.com/sitebuilder/images/DSC_0040-803x536.jpg

  11. Coat Color in Horses • C= Color gene • CRCR  = Red • CWCW= White • CRCW= Red Roan • If you cross a true breeding Red horse with a true breeding white horse, what ratios will you get? Genotypic Ratio: All CRCW Phenotypic Ratio: All Red Roan

  12. Example: MN Blood Group • MN blood group – is characterized by a certain type of glycoprotein on the surface of the RBCs. • There are two forms: M and N • Designate is L • LMLM = M • LNLN = N • LMLN  = MN type

  13. MN Blood Group • LMLM = M • LNLN = N • LMLN  = MN type • What types of offspring would be produced from a cross of a homozygous M type with an MN type? • Parents: LMLM X LMLN • Genotypic Ratio: 1 LMLM : 1 LMLN • Phenotypic Ratio: 1 M blood type: 1 MN blood type

  14. Multiple Alleles • More than two alleles for a gene

  15. O (ii) is recessive to IA and IB. • Genotypes IAIAand IAi result in Type A phenotype. • Genotypes IBIB and IBi result in Type B phenotype. • Genotype IAIBresults in Type AB phenotype (codominant). • Genotype ii results in Type O phenotype.

  16. Surface proteins are like nametags and antibodies clump up foreign blood • Useful in blood transfusion and organ transplant

  17. Resource Sites • Incomplete & Codominance Explained: • http://www.hobart.k12.in.us/jkousen/Biology/inccodom.htm • Codominance - Incomplete Dominance (Brightstorm Video) • http://www.brightstorm.com/science/biology/mendelian-genetics/codominance-incomplete-dominance/ • Practice: Drag and Drop Pedigrees • http://www.zerobio.com/drag_gr11/pedigree/pedigree4.htm • More Practice from KSU: • http://www.ksu.edu/biology/pob/genetics/incom.htm

More Related