1 / 15

Chapter 8 Notes (Day 5)

Chapter 8 Notes (Day 5). Objective: 1) Provide an example for codominance, incomplete dominance, and multiple alleles. 2) Define karyotype. SIMPLE DOMINANT HEREDITY. SOME TRAITS THAT ARE DOMINANT INCLUDE: HITCHHIKER’S THUMB, ALMOND-SHAPED EYES, THICK LIPS, HAIR ON MIDDLE SECTION OF FINGER.

adele
Download Presentation

Chapter 8 Notes (Day 5)

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. Chapter 8 Notes (Day 5) Objective: 1) Provide an example for codominance, incomplete dominance, and multiple alleles. 2) Define karyotype.

  2. SIMPLE DOMINANT HEREDITY SOME TRAITS THAT ARE DOMINANT INCLUDE: HITCHHIKER’S THUMB, ALMOND-SHAPED EYES, THICK LIPS, HAIR ON MIDDLE SECTION OF FINGER. .

  3. Human Traits:  autosomal Return to Menu

  4. WHEN HEREDITY FOLLOWS DIFFERENT RULES INCOMPLETE DOMINANCE: THE PHENOTYPE OF THE HETEROZYGOUS CONDITION IS A CROSS BETWEEN THE DOMINANT AND RECESSIVE TRAITS. EXAMPLE: IN CARNATIONS, R=RED r=WHITE RR= RED CARNATION Rr= PINK CARNATION rr= WHITE CARNATION

  5. CODOMINANCE: THE PHENOTYPES OF BOTH ALLELES ARE EXPRESSED IN A HETEROZYGOUS INDIVIDUAL. EXAMPLE: IN CHICKENS, B= BLACK FEATHERS, W= WHITE FEATHERS BB = BLACK FEATHERS BW = BLACK AND WHITE FEATHERS WW = WHITE FEATHERS

  6. MULTIPLE ALLELES: SOMETIMES MORE THAN 2 ALLELES CONTROL A TRAIT. 3 ALLELES DETERMINE PIGEON FEATHER COLOR

  7. Epistasis Occurs when one gene controls the expression of a second gene. In mice, one gene controls whether the mouse will have coloration (dominant) or albinism/white (recessive). IF coloration is dominant, THEN a second gene will determine if the mouse will be brown or black.

  8. Pleiotropy Pleiotropy is a condition that occurs when 1 gene controls many phenotypes. A classic example of pleiotropy is the human disease PKU (phenylketonuria). This disease can cause mental retardation and reduced hair and skin pigmentation, and can be caused by a mutation in a single gene that codes for an enzyme (phenylalanine hydroxylase) that converts the amino acid phenylalanine to tyrosine, another amino acid.

  9. Polygenic Inheritance One trait or phenotype is controlled by many genes. For example between 4 to 10 genes control human height. Genes linked to human height: ZBTB38, HHIP, CDK6, HMGA2, GPR126, ADAMTSL3, GDF5, LCORL, EFEMP1, and HIST1H1D

  10. SEX CHROMOSOMES AND SEX-LINKED TRAITS AUTOSOMES: THERE ARE 22 PAIRS OF HOMOLOGOUS CHROMOSOMES (TOTAL CHROMOSOMES =44) SEX CHROMOSOMES: 1 PAIR OF CHROMSOMES THAT DETERMINE THE SEX OF AN ORGNANISM. SOME TRAITS ARE CONTROLLED BY GENES LOCATED ONLY ON THE SEX CHROMOSOMES (EXAMPLE: COLOR BLINDNES AND HEMOPHILIA).

  11. YOUR CHROMOSOMES DURING METAPHASE YOUR CHROMOSOMES ORGANIZED AS A KARYOTYPE (CHROMOSOME MAP)

  12. SEX-LINKED INHERITANCE SEX-LINKED TRAITS: TRAITS CONTROLLED BY GENES LOCATED ON THR SEX CHROMOSOMES. X = FEMALE SEX CHROMOSOME Y = MALE SEX CHROMOSOME (SMALLER THAN X AND DOES NOT CONTAIN AS MANY GENES)

  13. THOMAS HUNT MORGAN DISCOVERED TRAITS LINKED TO SEX CHROMOSOMES. HE FIRST NOTICED THIS IN FRUIT FLY EYE COLOR. MORGAN’S 1ST EXPERIMENT: X FEMALE MALE Xr Y XRXr XRY OFFSPRING: ALL RED EYES XR XRY XRXr XR

  14. THOMAS MORGAN

More Related