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Genetic Material. C hromosomes are found in the nuclei of an organism’s cells. They are tightly coiled strands of DNA. DNA is a very long molecule that holds specific codes for specific traits. These codes are called genes .
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Genetic Material • Chromosomes are found in the nuclei of an organism’s cells. They are tightly coiled strands of DNA. • DNA is a very long molecule that holds specific codes for specific traits. These codes are called genes. • Genes are segments of DNA made up of base pairs (A,T, C, G) that are arranged in a very specific order. • Genetic abnormalities are caused by random changes in genes, called mutations.
The Human Genome • We have 23 homologous pairs of chromosomes (46 total) in the nuclei of our cells. You get 23 from each parent and the similar ones pair up. The pair, of “sex chromosomes” determines if you are a male or female. XX = female and XY = male.
Heredity • Inherited traits are passed on from parents to offspring. • Acquired traits appear during life.
Asexual Reproduction • Simple organisms like bacteria, protists and fungi reproduce asexually. In this process, a cell makes an exact copy of its own DNA, doubles in size, and splits into two identical cells. No mate is needed. This is basically the same process that complex organisms use to build new cells for growth and repair.
Sexual Reproduction • Two parents both contribute DNA to the offspring. The result is genetically unique offspring. • Plants and animals reproduce this way.
Simple Mutations • We all have mutations in our DNA. Most mutations have little or no effect on the expression of traits. A mole is an example of a simple mutation in skin cells. Over time, however, further mutations can cause a “beauty mark” to become cancerous.
Significant Mutations • Down Syndrome is a genetic disorder that results from having 3 copies of chromosome 21, instead of 2 copies (1 from each parent).
Hypertrichosis is a rare genetic disorder. Only about 50 cases of the condition have been documented since the Middle Ages. Fajardo Aceves Jesus Manuel of Mexico
Crowds are flocking to Indian temples to see a Muslim baby with a 'tail' who is believed to be the reincarnation of a Hindu god. The 11-month-old boy has been named Balaji or Bajrangbali, another name for monkey-faced Lord Hanuman. He is reported to have a 4in 'tail' caused by genetic mutations during the development of the fetus. Iqbal Qureshi, the child's maternal grandfather, is taking Balaji from temple to temple where people offer money to see the boy. Mr Qureshi says the baby has nine spots on his body like Lord Hanuman and showed them to journalists, reports Indian newspaper The Tribune.
Stumpy, a four-legged duckling, has become an unlikely national hero after thriving in spite of his rare genetic deformity
Big Wendy Normal Whippet
A two-headed red slider turtle at Big Al's Aquarium in Pennsylvania. Photo: AP
A white American alligator shows a genetic mutation known as leucism. This gene controls migration of pigment cells during development; absence in cells leads to white patches on the skin.
DNA Profiling • A technique used by forensic scientists to identify individuals based on their DNA. • We all have the same basic DNA structure, but every person has unique patters in their DNA that can be identified using this common procedures. • Since DNA is found in the nuclei of every human cell, forensic scientists can use hair, blood or skin tissue for DNA profiling.
DNA and Evolution • DNA is used as evidence for theories about the evolution of living things. By comparing the DNA of different species of living things, scientists are able to determine how similar they are, and how closely related they might be. • Comparing human DNA patterns around the world has allowed scientist to develop theories about human migration from the time of the earliest humans to the present.
StemCellResearch • Stem cells are cells that are not yet specialized. They can be found in a developing embryo or in the bone marrow of an adult. • Stem cells can now be grown and transformed into specialized cells, like muscle or nerve cells. • Stem cells can and will be used to treat a wide variety of diseases and disabilities because they can generate new tissues and organs.
Cloning Cloning Cloning • The first cloned animal, Dolly, was cloned in 1997 by Ian Wilmut from Edinburgh University, Scotland. • Many other animals have been cloned since, including family pets!
Genetically Modified Foods • Genetically modified (GM) foods are food items that have had their DNA changed through genetic engineering. • Genetically engineered crops and foods are controversial, for many reasons.
