Bio Ch 15 - The Human Genome

human genome

the full set of genetic information that a human carries in its DNA

karyotype; what is shows

-photograph of anindividual's complete diploid set of chromosomes
-shows: total # of chromosomes, gender, and disorders

how are karyotypes made?

- homologous chromosomes are paired in order of decreasing size
- homologous pairs can be determined by centromere placement as well as similar band placement

autsomes

chromosomes 1-22 of humans

sex chromosome

chromosome #23

female chromosomes

XX

male chromosomes

XY

4 blood types

A, B, AB, O

universal donor

O

universal receiver

AB

Where do alleles produce antigens?

on red blood cells

possible alleles for blood type A

I^A I^A or I^A i

possible alleles for blood type B

I^B I^B or I^B i

possible alleles for blood type AB

I^A I^B

possible alleles for blood type O

i i

+ and - comes from factor called

Rhesus

_____ is dominant over ______ for blood types

+ is dominant over -

sex linked gene

gene located on a sex chromosome

occurance on color blindness in males

1 in 12

occurance of color blindness in females

1 in 200

What chromosome is color blindness found on?

X chromosome

most common type of color blindness

red-green color blindness

Is color blindness dominant or recessive?

recessive

Why do males only need 1 gene for color blindness while females need 2?

- males have 1 X and 1 Y
- if he inherits X w/color blindness he will express color blindness bc there's no other X to stop it
- females have 2 X's
- in females, there can be another X w/o color blindness so that it wont be expressed

human pedigree

a chart that shows relationships within a family and how traits are passed down; shows presence or absence of a trait

chromosomal disorder

a disorder that is the result of alteration in an entire chromosome

most common cause of chromosomal disorder

nondisjunction

most common chromosomal disorder

down sydrome

nondisjunction

failure of chromosomes to separate during meiosis

another name for down syndrome

trisomy 21

common sex chromosome disorders

i. turners sydrome - only females
ii. Kleinfelters syndrome - only males

turners syndrome notation

(45, X) missing X

kleinfelters syndrome notation

(47, XXY) extra X

(pedigree) circle is

female

(pedigree) square is

male

(pedigree) shaded in is

expressed

(pedigree) no shaded in is

not expressed

DNA can be ________ and __________ by process of __________.

separated and compared by gel electrophoresis

gel electrophoresis

a mixture of DNA fragments are put into a gel and an electric current is applied

how does gel electrophoresis work?

- negatively charged particles of DNA move to positive end
- faster = smaller/less dense
- slower = bigger/more dense

What does gel electrophoresis show? What is it used for?

- can be used to compare one gene out of thousands of genes in an individual
- can compare different people's DNA

How is gel electrophoresis useful in law/people/science?

Unique portions of DNA can be used to compare an individual's DNA to another to show familial relationships, determine if you were at the crime scene or not, etc. (used to find similarities and differences in DNA samples)

Polymerase Chain Reaction

the technique used by biologists to make many copies of a particular gene > once enough of sample of DNA is achieved, it can be studied or compared to a known sample

restriction enzyme

Enzyme that cuts DNA at a specific sequence of nucleotides > help scientists focus on smaller portions