1 / 18

Genetics Terminology

Genetics Terminology. Trait -characteristic or quality EX: Tongue rolling. The gene codes for the trait. There are 2 versions of the gene called Alleles. Can roll tongue = Dominant = T Cannot roll tongue. = Recessive = t

Télécharger la présentation

Genetics Terminology

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. Genetics Terminology • Trait-characteristic or quality • EX: Tongue rolling. • The gene codes for the trait. There are 2 versions of the gene called Alleles. • Can roll tongue = Dominant = T • Cannot roll tongue. = Recessive = t Each trait receives two alleles, one from the mother, one from the father.

  2. Homozygous: all of the same alleles. • TT or tt • Heterozygous: Different alleles • Tt • Genotype: Phenotype • TT : Rolls Tongue • Tt : Rolls Tongue • tt : cannot roll • Phenotype: Physical/feel • Genotype: Genes • Trait-characteristic or quality • EX: Tongue rolling. • The gene codes for the trait. There are 2 versions of the gene called Alleles. • Can roll tongue = Dominant = T • Cannot roll tongue. = Recessive = t Each trait receives two alleles, one from the mother, one from the father.

  3. Genetic Crosses • Monohybrid: one trait • Dihybrid: two traits • Working backwards with you -grandparents: P generation - parents : F1 Generation -You: F2 generation Test Cross: used to determine if a phenotypically dominant individual is homozygous or heterozygous True-breeding: homozygous for a trait. • Homozygous: all of the same alleles. • TT or tt • Heterozygous: Different alleles • Tt • Genotype: Phenotype • TT : Rolls Tongue • Tt : Rolls Tongue • tt : cannot roll • Phenotype: Physical • Genotype: Genes

  4. Test Cross • Unknown dominant x known recessive • See example on the board • Look at the offspring of the test cross to determine if it is heter or homozygous. • Monohybrid: one trait • Dihybrid: two traits • Working backwards with you -grandparents: P generation - parents : F1 Generation -You: F2 generation Test Cross: used to determine if a phenotypically dominant individual is homozygous or heterozygous

  5. 9,10,11 • 10. • B ½ • C. ¼ • 11. • A. 1/8 • B. 1/32 • C. 1/32 • D 1/32

  6. Complete Dominance • “Normal” dominance • The dominant allele is completely expressed over the recessive allele.

  7. Incomplete Dominance • Incomplete = IN between • The heterozygous genotypes have a phenotype that is IN between the two homozygous genotypes • Red-Pink-White • RR – Rr - rr

  8. Codominance and Multiple Alleles • Co dominant= Co-captains of equal strenth on a team. • The heterozygous alleles are equally expressed • Multiple alleles. An additional allele can represent the recessive.

  9. Pleiotropy-one gene has many effects Epistatis-one gene affects the expression of another gene  BbCc BbCc Sperm 1/4 1/4 1/4 1/4 BC bC Bc bc Eggs 1/4 BC BBCc BBCC BbCC BbCc 1/4 bC bbCC bbCc BbCC BbCc 1/4 Bc BBcc Bbcc BBCc BbCc 1/4 bc BbCc bbCc Bbcc bbcc : 4 9 : 3 More non-Dominant Inheritance

  10. Polygenic Inheritance-Many alleles develop a trait. Example: Skin Color Role of the environment  AaBbCc AaBbCc Sperm 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 Eggs 1/8 1/8 1/8 1/8 Phenotypes: 1/64 6/64 15/64 20/64 15/64 1/64 6/64 Number of dark-skin alleles: 2 6 0 3 4 5 1 Non-Dominant Inheritance

  11. Law of Segregation Law of Independent Assortment The 2 alleles that each parent has for a trait separate to make sex cells The alleles will be random in the sperm and egg. Ch 15-mostly review

  12. Grasshoppers = two x is female, one x is male Z-W system is opposite humans, females determine Bees-diploid are females, haploid are males. 44 + XX 44 + XY Parents 22 + X 22 + X 22 + Y or + Sperm Egg 44 + XX 44 + XY or Zygotes (offspring) (a) The X-Y system 22 + XX 22 + X (b) The X-0 system 76 + ZW 76 + ZZ (c) The Z-W system 32 (Diploid) 16 (Haploid) (d) The haplo-diploid system Not all like humans

  13. W+ is wild type, usually dominant always homozygous. • Only male flies can have white eyes if they receive their only x from the mutant x.

  14. XnY XnY XNXN XNXn  XNY XNXn   Sperm Sperm Sperm Xn Y XN Xn Y Y Eggs Eggs XNXN Eggs XNXn XNY XN XNY XN XNXn XNY XN XnXn XnY XNXn XNY XnXN XnY Xn Xn XN (a) (b) (c) Colorblindness: males are more affected than females. Gene is located on X chromosome, heterozygous females are carriers.

  15. Fig. 15-15 A B C D E F G H A B C E F G H Deletion (a) A B C D E F G H A B C B C D E F G H Duplication (b) A B C D E F G H A D C B E F G H Inversion (c) A B C D E F G H M N O C D E F G H (d) Reciprocal translocation M N O P Q R A B P Q R

  16. Quiz on Wednesday:chapter 16 • A, T, C, G bonds • Purines vs. Pyrimidine • 5’-3’ order • Replication, Transcription, Translation • Helicase, Leading and Lagging strand,

More Related