1 / 31

SEX LINKED TRAITS

SEX LINKED TRAITS. These are the genetic traits often found more in one gender than the other. Every pair of chromosomes in our human cells are identical – except one. The 23 rd pair of chromosomes is different. They either look like an X or a Y. FEMALE = XX MALE = XY.

keegan-moody
Télécharger la présentation

SEX LINKED TRAITS

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. SEX LINKED TRAITS These are the genetic traits often found more in one gender than the other

  2. Every pair of chromosomes in our human cells are identical – except one. The 23rd pair of chromosomes is different. They either look like an X or a Y. FEMALE = XX MALE = XY

  3. So how is gender determined from a genetic standpoint?Let’s make a Punnett Square. Cross XY x XX

  4. PunnettSquare XY x XX X X X Y

  5. 50% XX 50% XY X X X X X X X X Y X Y Y

  6. 50% XX 50% XY X X X X X X X Girl Girl X Y X Y Y Boy Boy

  7. THE GENES FOR A SEX LINKED TRAIT ARE FOUND ONLY ON THE X CHROMOSOME.

  8. SEX LINKED TRAITS SOME EXAMPLES OF SEX LINKED TRAITS ARE… COLOR BLINDNESS & HEMOPHILIA

  9. THE ALLELES THAT PRODUCE THESE TRAITS ARE RECESSIVE.

  10. FOR A FEMALE TO SHOW ONE OF THESE TRAITS SHE MUST HAVE BOTH RECESSIVE ALLELES (like normal).

  11. FOR A MALE TO SHOW ONE OF THESE TRAITS HE NEEDS TO HAVE ONLY ONE RECESSIVE ALLELE (he doesn’t have another X chromosome to cover it up!).

  12. X This piece is missing

  13. X The gene is on this piece

  14. SEX LINKED TRAITS Let N = normal vision Let n = Color Blind

  15. We put the allele on the X chromosome so we can identify it as a sex-linked trait

  16. A female that has normal vision can have one of these genotypes.

  17. XNXN or XNXn

  18. SEX LINKED TRAITS A male with normal vision can have only ONE genotype

  19. SEX LINKED TRAITS XNY

  20. A female with color blind vision would have ? Genotype?

  21. XnXn

  22. A male with color blind vision would have what Genotype?

  23. XnY

  24. Remember- A male need only have 1 recessive allele to be color blind

  25. SEX LINKED TRAITS Set up a Punnett square to show the following.

  26. Homozygous Normal female & Color Blind male.

  27. XNXN x XnY

  28. Xn Y XN XNXN x XnY Parent cross XN

  29. Xn Y XN XNY XNXn XNXN x XnY XN XNY XNXn

  30. Xn Y XN XNY XNXn XNXN x XnY XN Carrier female Normal male XNY XNXn Carrier female Normal male

  31. Remember – we use the X’s to designate that the gene is sex-linked. Otherwise the Punnett square is just like any other simple dominance problem.

More Related