When Does Life

Begin?

It’s a controversial topic, and different people have deeply-held beliefs. The ancient Greeks, for example believed that the “soul” entered a baby when it first laughed. What do you think?

Write down your response.

One Approach: The Legal Answer• Life begins at birth.– To be a legal person, you need to have been born first.

• Exceptions, etc.– Causing the death of a fetus can be a crime / damage– Abortion (Roe v. wade)• "For the stage prior to approximately the end of the first

trimester, the abortion decision and its effectuation must be left to the medical judgment of the pregnant woman's attending physician."

The Biological Answer• You became a distinct genetic individual at the moment of

fertilization. (NOT “conception” – that refers to the implantation of the zygote / embryo to the uterine linning.)

• Meiosis makes gametes, one half of a potential diploid individual.– Note: In

moss, the plant is haploid – so the new genetic individual is a result of meiosis, not fertilization

Dominant Haploidsn

n

2n

n

n n

Fertilization Creates a New Unique

Genetic Identity.

Your Biometric Identity

DNA Fingerprinting with Gel Electrophoresis

Gel Electrophoresis

• Gel electrophoresis separates DNA fragments based on their size.

• By cutting up DNA with enzymes, different organisms will have different DNA fragments

• You, and everyone else, has a nearly unique DNA fingerprint.

Gel Electrophoresis in Criminal

Investigations• Collect suspect & crime scene

DNA.• Amplify / copy DNA with PCR

with standard primers• Cut samples with same

restriction enzyme

• Separate DNA fragments by gel electrophoresis.

DNA Paternity Testing

• Each fragment seen in child sample must come from mother or father.

• Which gel has the right father?

Old HSA Question

• Which of the species shown is most closely related to species 1? Why?

Biotechnology Vocabulary

• Recombinant DNA is DNA that contains sequences from more than one species.

• Gene splicing is the process of inserting a gene into another organism’s DNA. (8:30 pt 1)

• Cloning is the process of making identical copies of DNA or organisms.

Recap

• New individual organisms are identifiable as a result of fertilization (or meiosis is haploid is dominant generation)

• Gel Electrophoresis is a way to uniquely identify people, and show relatedness.

• 3 other important DNA technology terms:– Recombinant DNA– Gene splicing– Cloning

Homework: On Syllabus

• Your test Friday (and the HSA) may include the information on the previous slide.

• DNA technology is covered in more detail in 13.1 and 13.2 in your book. I strongly suggest you read it, though there will be no graded assignment.

• Friday’s Test = chapters 8, 9, 10, + today. (Whole 3rd quarter so far)