JS 196e: Scientific Basis of DNA Typing continued and Methods used to Study DNA

I. Pre class activitiesa. Quizb. Assignment and announcements

II. Learning ObjectivesDefinition and Inheritance reviewIntroduction to DNA- continued

a. DNA structureb. Be able to draw DNA structure – Base

Pairing AT, GCc. Understand DNA replication

Summary of Introduction to DNA

Overview of Methods used in Forensic DNA typing ScreeningExtractionQuantification

Assignments and Announcements

• Friday 9 Feb: Guest lecture by Dr. Chris Chen of CCNY on nanotechnology- 1 point extra credit for attending and writing a 500 word summary

• Required assignments for 12 Feb– Work on Laboratory Notebooks – Study for a quiz– Read Butler C3/InmanC2– Review : Special collection guidelines for Biological Evidence-

http://www.cacnews.org/wordfiles/DNA%20SampleHandling.doc

Where’s Daddy?PCR product size (bp)

11 14

11

12 14

8 14

12

128

Inheritance Review

Dad is homozygous (A, A) and mom is heterozygous (A, a).

In your teams, draw the Punnett Sqaure that demonstrates the inheritance of these alleles.

What percentage of their children will be heterozygous?

DNA StructureWhat is it?

Bases (AGCT) form the stairs of the ladder, are faithfully paired and exhibit differences.

PS-A : T-SP PS-G : C-SP PS-A : T-SP PS-G : C-S P Sugars (S) and phosphates (P) form the sides of the ladder

(identical for all DNA).Bases (AGCT) form the stairs of the ladder, are faithfully paired by

hydrogen bonds and exhibit differences. A : T and G : C

A = T

G C

T = A

A = T

C G

T

C

C

A

G

G

T

A

G C

T = A

T = A

C G

A = T

A = TG C

5’

3’

3’

5’ 3’

3’ 5’denaturedstrands

hybridizedstrands

Hydrogen bonds

C G C

G

G C

Phosphate-sugar backbone