1 / 6

Sex-linked Traits

Sex-linked Traits. Ch. 10.5. Sex chromosomes. Humans- 23 rd pair of chromosomes- X,Y Eggs- Have an X chromosome. Sperm- Half have an X chromosome, half have a Y chromosome. Fathers determine gender(sex) of offspring. Males- XY Females- XX 50% chance of having a girl or boy offpring.

donnel
Download Presentation

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 Ch. 10.5

  2. Sex chromosomes • Humans- 23rd pair of chromosomes- X,Y • Eggs- Have an X chromosome. • Sperm- Half have an X chromosome, half have a Y chromosome. • Fathers determine gender(sex) of offspring. • Males- XY • Females- XX • 50% chance of having a girl or boy offpring.

  3. Sex-linked genes • Any gene on a sex chromosome- X or Y. • Majority are on X chromosome. • Examples- • Eye color in fruit flies- on the X chromosome • Red color is Normal and Dominant, XR • White color is Recessive. Xr • Females must have 2 recessive alleles to have white eyes. Xr Xr • Males need just 1 recessive allele ( they have only 1 X chromosome) Xr Y to have white eyes.

  4. Eye Color in Fruit flies

  5. Human X-linked recessive traits. • Hemophilia- bleeding disorder • Red-green color blindness. • more males with the disorder compared to females. • Females can be carriers- have one recessive allele- do not have the disorder, but can pass on the recessive allele to offspring. • Mothers pass trait on to sons. • Pedigree- Chart used to record and trace the occurrence of a trait in a family. • Squares- males • Circles- females. • Colored shapes- individuals that show the trait. • Parents are connected by horizontal lines(marriage line) • Children beneath them. • Generations – designated by Roman Numerals ( I, II, III etc) • Individuals are Numbered left to right in each generation.

  6. Sex-linked recessive pedigreeskips generations , see more often in males.

More Related