• Like
Handout: Human Genetics
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

Handout: Human Genetics

  • 435 views
Published

 

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
435
On SlideShare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
0
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Human Genetics
  • 2. Genetic Terms
    • A Gene is a specific region of DNA that directs the synthesis of a specific product. That product controls one or more specific traits.
    • Diploid cells have two copies of each gene, and the two copies segregate from each other during gametes formation.
    • Alleles are the different molecular forms of a gene.
    • Wild-type alleles are the most common form of a gene. The less common forms are referred to as Mutant alleles.
  • 3. Genetic Terms
    • Dominant alleles – the allele whose phenotype would dominate in a heterozygote (Aa).
    • Recessive allele – the allele whose phenotype would be dominated over in a heterozygote.
    • Heterozygote – two alleles of the same gene are not identical (Aa).
    • Homozygote – two alleles of the same gene are identical (AA).
    • Genotype – refers to the genetic make up of an individual.
    • Phenotype – refers to the outward appearance of an individual.
  • 4. More Genetic Terms
    • Crossing over during meiosis results in genetic recombination.
    • Independent assortment refers to the random alignment and assortment of each pair of homologous chromosomes during Meiosis I.
    • Abnormal changes in the structure of chromosomes and changes in chromosome number are referred to as mutations.
  • 5. Autosomes and Sex Chromosomes
    • Sex Chromosomes are types of chromosomes that, in certain combinations determine a new individual’s sex. (X and Y in humans)
      • Homologous pairs are usually not the same in length and shape.
    • Autosomes are all of the other chromosomes, which are the same in both sexes.
      • Homologous pairs are usually the same length and shape.
  • 6. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 XX (or XY) centrifugation Obtain cells and arrest them in metaphase with colchicine
  • 7. Sex Determination
    • Evidence has shown that every normal egg produced by a human female has one X chromosome and that half of the sperm cells produced by a male carry an X chromosome and half carry a Y chromosome.
  • 8. eggs sperm female (XX) male (XY) X X Y X XX XY XX XY X X Y X x x
  • 9. Sex Determination
    • If an X-bearing sperm fertilizes an X-bearing egg, the new individual will develop into a female.
    • If a Y-bearing sperm fertilizes an X-bearing egg, the new individual will develop into a male
    • The X chromosome carries 2,062 genes.
    • The Y chromosome carries only 330 genes.
      • However one of these genes is the master gene for male sex determination.
  • 10. The SRY Gene
    • A gene on the Y chromosome called SRY ( S ex determining R egion of chromosome Y ) is the master gene for male sex determination.
    • If a functional copy of this gene is present, testes form. If a functional copy is absent, ovaries form.