Heredity & Genetics Chapter 5.1 p. 120

Gregor Mendel The “Father of Genetics” An Austrian monk who lived during the mid 1800’s. He studied genetics using mainly pea plants.

What is Heredity? The passing of traits from parent to offspring What is a trait? A characteristic A characteristic

Genetics The study of how traits are inherited through interactions of alleles. Why is studying genetics important?

Allele The different forms of a trait that a gene may have Each parent gives the offspring one allele for each trait For example, one parent may give the offspring an allele for red hair. The other gives an allele for brown hair.

How can we use dominant and recessive alleles to predict traits of offspring? Probability and Punnett Squares!

How do you know which trait will “win?” Table 1 p. 122 Dominant Alleles Dominates recessive traits Dominates recessive traits Recessive Alleles Only expressed if alleles from both parents are recessive

Genotype vs. Phenotype Genotype The letters that represent dominant and recessive alleles The letters that represent dominant and recessive alleles Ex. Bb, bb Ex. Bb, bbPhenotype The way that the organism looks as a result of the genotype Ex. Brown hair, blue eyes

Homozygous vs. Heterozygous Alleles Homozygous An organism with two alleles that are the same An organism with two alleles that are the same Ex. TT, tt Ex. TT, ttHeterozygous An organism that has two different alleles for a trait Ex. Tt

Hybrids What is a hybrid? A cross of two or more components A cross of two or more componentsMonohybrid Crossing one trait Crossing one traitDihybrid Crossing two traits Crossing two traits

Punnett Squares Used to predict the traits (alleles) that will be inherited by the next generation of offspring

Making A Punnett Square to predict probablity p. 125 A Punnet square can give the probability (chance) that certain traits will appear in the next generation.

UmMs UmMs

Punnett Square Practice (Monohybrid) Cross a male dog that is heterozygous for black fur and a female dog that is homozygous for blonde fur Step 1: Assign both genotypes letters Step 2: Set up a grid Step 3: Determine the probability of alleles

Chapter 5: Section 2 “Genetics Since Mendel” p. 128

Incomplete Dominance When the offspring of two homozygous parents display a trait that is a blend of dominate and recessive Ex. A red and white flower = pink flower

Co - Dominance In COdominance, the "recessive" & "dominant" traits appear together in the phenotype of hybrid organisms.

Polygenic Inheritance Many alleles (not just dominate and recessive) working together to produce a trait Ex. Skin color, height, eye color

Effect of Environment on Genetics Although genes determine many of your traits, environment plays a role in how some of your genes are expressed or whether they are expressed at all. Ex. Tanning or limiting exposure to the sun Question: What environmental factors might affect the size of leaves on a tree?

Genetic Disorders Recessive Genetic Disorders: Occur when both parents are Heterozygous for the disease, but do not have the disease. They are called “carriers.” Ex. Cystic Fibrosis

Genetic Disorders Down’s Syndrome A result from 3 copies of chromosome 21 Individuals with Down’s can exhibit learning disabilities and have heart problems, but can also lead “normal” lives

Different Colored Eyes “Heterochromia” Eye Color is polygenic Eye colorEye color is the result of how much pigment is made in the front part of the eye. Eye color The amount of pigment is controlled by genes in special cells called melanocytes. One way to end up with two different colored eyes is when an eye color gene works in one eye but not the other.

Albinism The cause of albinism is a mutation in one of several genes involved in the production of melanin. A mutation may result in no melanin production at all or a significant decline in the amount of melanin. In most types of albinism, a person must inherit two copies of a mutated gene — one from each parent — in order to have albinism (recessive inheritance). If a person has only one copy, then he or she won't have the disorder.

Tracing Traits Pedigree = A visual diagram that follows a trait through generations Used to trace disease or breeding plants & animals

Chapter 5: Section 3 “Biotechnology” p. 135

What is Biotechnology? Hint: Use your root word skills! Biotechnology = The application of the principles of engineering and technology to the life sciences; bioengineering.

Genetic Engineering Through genetic engineering scientists can change the arrangement of DNA that make up a gene. What are the benefits of genetic engineering? Improving crop & livestock production Curing diseases Gene Therapy (p. 136)

Francis Crick & James Watson Discovered the double helix structure of DNA in 1953

Severo Ochoa Severo Ochoa was a Spanish-born U.S. scientist. In 1959, he was awarded a Nobel Prize for discovering an enzyme that enables the synthesis of RNA, enabling scientists to recreate the cell process which translates hereditary genes. Severo Ochoa was a Spanish-born U.S. scientist. In 1959, he was awarded a Nobel Prize for discovering an enzyme that enables the synthesis of RNA, enabling scientists to recreate the cell process which translates hereditary genes.

Barbara McClintock Botanist who found that some corn plant genes appeared to move from cell to cell during development of corn kernels. She discovered that the genes moved on and between chromosomes. In 1983, when she was 81, she was awarded a Nobel Prize for her discoveries. This made McClintock the first American woman to win an unshared Nobel.

An international scientific research project that began in 1990 with a primary goal of determining the sequence of chemical base pairs which make up DNA, and of identifying and mapping the approximately 20,000–25,000 genes of the genome.