Reproductive Technologies, Pedigrees, Codominance +

Cloning

Way to produce a genetically identical organism through non-sexual means. Used to produce plants for many years (using cuttings).

First animal to be cloned

Dolly the sheep

Cell used to make dolly the sheep

body/somatic cell

Examples of other animals scientists have cloned

Mice, cows, cats, dogs

Problems with cloning

Low success rates —> many embryos do not survive.

Health issues, premature aging, or genetic abnormalities.

Explanation of how Dolly the sheep was made

A donor cell was taken from a sheep’s udder (donor nucleus) and an egg cell was taken from an adult female sheep. The nucleus of the egg cell is removed, and the two cells are fused together using an electric shock. The fused cell begins dividing normally and becomes an embryo. The embryo is placed in the uterus of a foster mother. The embryo develops normally into a lamb (Dolly!)

Purpose of cloning

To mass produce organisms with desired qualities.

Example: sheep have been engineered to produce human insulin.

Also: to replace lost or deceased family pets or to repopulate an endangered or even extinct species.

Social, moral, and ethical controversy surrounding cloning: positive side

People for cloning think it could be used to replace deceased relatives or harvest organs from a clone to remove the chance of rejection.

Social, moral, and ethical controversy surrounding cloning: negative side

To create Dolly, scientists performed the experiment 276 times, which means many failures.

Cloning could also potentially be used to add more people to a certain race, political party, religion, background, sex, physical appearances, special talents, etc.

People could select traits for their children.

To harvest organs, the clone would have to be killed.

Therapeutic cloning

Based on the concept that the best ways to get stem cells that are a perfect fit for a patient — thereby preventing immune rejection — will be to create a clone of that patient, develop the embryo to around 100 cells, then remove the stem cells.

Researchers consider the technique promising for treating spinal cord injuries and Alzheimer’s disease.

Percentage of couples affected by infertility

10%

Amount of babies that have been born as a result of IVF

More than 25,000

Why couples might use IVF

For women with fallopian tube problems or men with mild sperm problems

Cost of IVF per try

$15,000-$20,000 CAD

Process of In-vitro fertilization

Women take hormones to prepare their eggs and uterus for pregnancy. A man’s sperm and a woman’s egg are combined in a petri plate in a lab. The resulting embryo is transferred to the woman’s uterus to implant and develop. Usually 2-4 are implanted at a time to improve the likelihood.

Explain artificial insemination (intrauterine insemination)

Sperm is artificially placed into a woman’s cervix or uterus. Semen to be implanted is “washed” in a laboratory, concentrating the semen and removing any harmful chemicals. The semen is inserted into the woman, and if the procedure is successful, she conceives.

What is codominance?

When two different alleles of the same gene are fully expressed together in a heterozygous organism; one trait is NOT masked by the other.

What is incomplete dominance?

A genetic pattern where a heterozygous organism shows an intermediate, blended phenotype because neither allele fully dominates the other.

Multiple alleles

Refers to a gene that has more than two possible forms in a population, although an individual can only carry two possible alleles of that gene.

Universal blood donor

O negative (or Rh null, though more rare).

Blood antigens

Molecules, usually proteins or carbohydrates, located on the surface of red blood cells that help the immune system distinguish self from non-self.

Difference between negative blood type and positive blood type.

The presence of Rh factors (D antigens) on red blood cells. Blood cells with this protein are positive, and blood cells without this protein are negative. 85 percent of people have D-antigen, whereas 15 percent do not have this protein.

What are pedigrees?

The recorded ancestry of a person or family.

Maternal Blood Testing

A form of prenatal testing: blood is drawn between 15th and 22nd week of pregnancy.

Ultrasound

A form of prenatal testing: sound waves produce a visual scan of the fetus.

Amniocentesis

A form of prenatal testing: sampling amniotic fluid with fetal cells

Chorionic Villi Sampling

A form of prenatal testing: Placental tissue sample taken