Section 6-4 “Traits & Genes ”

Section 6-4“Traits & Genes” Write everything that is underlined

KEY CONCEPT Genes encode proteins that produce a diverse range of traits

Important Vocabulary Terms for You to Know Please make a chart or table at the top of your notes for these vocabulary terms: • Gene • Allelle • Homozygous • Heterozygous • Genome • Genotype • Phenotype • Dominant • Recessive

A. The same gene can have many versions 1. A gene is a piece of DNA that tells a cell to make a certain protein • Each gene has a locus, a specific position on a pair of homologous chromosomes

2. An allele is an alternative form of a gene • -Each parent donates one allele for every gene • Pea plants have 2 alleles for shape - they receive one from each parent • For shape, there is a wrinkled allele and a round allele

B. Genes influence the development of traits • All of an organism’s genetic material is called the genome • A genotype refers to the actual genes • A phenotype is the physical expression of a trait

C. Genotype: 1. The gene combination of an organism • It consists of 2 alleles • For example: • Pure dominant, 2 dominant genes • Pure recessive, 2 recessive genes • Hybrid, 1 dominant and 1 recessive gene

D. Phenotype: 1. The way an organism looks • No matter what genes are present, phenotype of a tall pea plant is tall and a short pea plant is short

A dominant allele is expressed as a phenotype when at least one allele is dominant • A recessive allele is expressed as a phenotype only when two copies are present • 2. Dominant alleles are represented by uppercase letters • 3. Recessive alleles by lowercase letters

Think fast!!! • Determine if the following is genotype or phenotype. • A horse with white stockings • A pink rose that was bred from a white rose and red rose • A pig that has super heavy muscling

E. Mendel’s observed traits • Dominant traits: covers up the other traits • Recessive traits: traits that “disappear” • Rule of Dominance: When a dominant trait is present the recessive trait is hidden

How’s it related???? • You have 4 minutes and 25 seconds to draw a concept map to show (with words, chart, or a concept map) how these terms are related. • Gene • Genotype • Phenotype • Allelle • Dominant traits • Recessive traits

Most traits occur in a range and do not follow simple dominant-recessive patterns

F. The Law of Independent Assortment: • Genes for different traits are inherited independently of each other • When you have 2 or more different traits they are not “stuck” together

Example (for your genetics book) • Seed types of Parents: • Wrinkled,yellow • Round,green • You can get offspring with: • Wrinkled, green seeds • Or Round, yellow seeds

Section 6-4 “Traits & Genes ”