Multi-Allelic Traits

1. Blood Type

iA, iB, iAB, & iO

2. Skin Color

3. Eye Color

4. Hair Color

Mitosis v Meiosis

aka…Battle of the -Osis-es

Mitosis

1. Asexual

2. Body cells (occurs in all organisms)

3. Prophase, metaphase, anaphase, telophase

4. Results in two daughter cells.

5. New cells have normal number of

chromosomes (2N-diploid)

6. New cells fully functional.

Meiosis

1. Sexual

2. Gametes (animals and plants)

3. Prophase, metaphase, anaphase, telophase…twice!

4. Results in four daughter cells.

5. New cells w/ ½ normal number of

chromosomes (N-haploid).

6. New cells need to combine with another gamete before

they’re fully functional.

Sex-Linked Traits

Human’s have 23 pairs of chromosomes…46.

Pair number 23 determines the sex of the

person. XX=girl…XY=boy.

These are traits that are only on one of the sex

chromosomes in the 23rd pair (the X or Y).

Many traits and disorders are recessive. This

means that if a female gets the recessive trait on

one X chromosome…she has a chance to get

the dominant allele on the other X chromosome,

which cancels it out. If you’re a guy and it’s on

your X…you got it! Period! Sorry guys.

Examples of Sex-Linked Traits

Colorblindness

a problem with the color-sensing cones in the retina of the eye.

You can’t see certain colors

Red/Green-most common

Blue Yellow

Achromatopsia-see greys only

Hemophilia

Blood lacks clotting

factor, most of which

are produced in the

liver.

Type A and

B…different factors

are missing.

Genetic Disorders 1. Down Syndrome: aka Trisomy 21.

Caused by an extra chromosome (or part

of one) at the 21st pair.

• Chromosomes do not properly separate

during meiosis (nondisjunction).

1. Kleinfelter’s Syndrome:

XXY syndrome. Also from meiotic

nondisjunction.

2. Turner’s Syndrome: females missing one

x chromosome.

3. Sickle-Cell Anemia: mutation of a single

nucleotide. There’s a GTG where a

GAG should be. That’s it…one little

change. It’s on the short part of

chromosome 11…in case you’re lookin’.

Cystic Fibrosis

Autosomal Recessive (that means NOT on a sex chromosome).

On the #7 chromosome.

Prevents proper formation of a protein that is involved in lung and digestive system function.

Mucous builds up and this creates an environment where bacteria thrive.

Pedigrees

Try to Create this one based upon

the following case study

Jim and Cindi have three kids: 1 boy and 2 girls.

Girl #1 appears healthy.

Girl #2 and Boy have empty-head syndrome (a recessive trait ee).

Cindi’s dad has EHS but Cindi does not.

Jim and his parents don’t have symptoms.

Jim’s grandfather on his mom’s side had EHS.