Chapter_15 - (a) Hydra Parent Bud 0.5 mm Chapter 15 The...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: (a) Hydra Parent Bud 0.5 mm Chapter 15 The Chromosomal Basis of Inheritance 0.5 mm Meiosis Metaphase I Anaphase I Metaphase II Gametes LAW OF SEGREGATION The two alleles for each gene separate during gamete formation. LAW OF INDEPENDENT ASSORTMENT Alleles of genes on nonhomologous chromosomes assort independently during gamete formation. 1 4 yr 1 4 Yr 1 4 YR F 1 Generation 1 4 yR R R R R R R R R R R R R Y Y Y Y Y Y Y Y Y Y Y Y y r r r r r r r r r r r r y y y y y y y y y y y All F 1 plants produce yellow-round seeds (YyRr) 1 2 2 1 Review of Mendel’s Laws F 2 Generation An F 1 × F 1 cross-fertilization 9 : 3 : 3 : 1 You should be comfortable using probablities to determine the outcome of genetic crosses. Let’s try some examples Parent Bud 0.5 mm Genes linked to sex chromosomes were first found in Drosophila P Generation Generation Generation Generation Generation Generation F 1 F 2 All offspring had red eyes Sperm Eggs F 1 F 2 P Sperm Eggs × × X X X Y CONCLUSION EXPERIMENT RESULTS w w w w w w w w + + + + + w w w w w w w w w + + + + + + Normal segregation ratios for white-eyed mutation in F1 and F2 generations, but affected individuals were all male. Females can have the trait, though. How? X Y In humans the 22 pairs of autosomes contain the same genetic material on each homolog. The sex chromosomes differ greatly in size and genetic content. This leads to some funky genetics for genes on these two mis-matched chromosomes. 44 + XY Parents 44 + XX 22 + X 22 + X 22 + Y or + 44 + XX or Sperm Egg 44 + XY 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 Various Chromosomal Sex Determination Systems Fig. 15-7 (a) (b) (c) X N X N X n Y X N X n × × X N Y X N X n × X n Y Y X n Sperm Y X N Sperm Y X...
View Full Document

This note was uploaded on 01/27/2011 for the course BIOL 112 taught by Professor Vaughn during the Fall '08 term at Texas A&M.

Page1 / 27

Chapter_15 - (a) Hydra Parent Bud 0.5 mm Chapter 15 The...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online