4.1 Living Things Inherit Traits in Patterns Mrs. Leos May 20, 2015

SO FAR…… We have learned that: Cells contain chromosomes NOW we will learn about: How genes for traits are passed from parent to offspring More about Gregor Mendel Dominant and recessive alleles

Genetics The study of gene structure and the patterns of inheritance of traits from parent to offspring.

Traits Inherited Hair color, eye color, blood type Traits passed from parent to child Acquired Ability to read, skills learned

Genes Made of DNA Control traits that show up in an organism Sections of the chromosome shown here have been coloured in. Each section is a piece of DNA called a gene.

Heredity Passing of traits (genes) from parent to offspring

Alleles alternative forms of the same gene Each allele occupies same position on length of chromosome Gene for hair color, allele could be blonde, brown or red

Multiple Alleles A trait is controlled by more than two alleles Blood Type A&B =AB Curly hair & straight hair= wavy hair Brown Eyes & Green Eyes =Hazel eyes Alleles are considered to be co-dominant Co-dominant-both show up

Human Chromosome Number 46

Sex Chromosomes X-chromosome Y Chromosome XX=Girl XY=Boy

Gregor Mendel- Father of Genetics Science of how trait are inherited through alleles 1856 studied garden peas for height, flower and pod position, seed shape, seed color, pod shape, pod color, flower color

Mendel Success Mendel figured how traits were transmitted from parent to offspring. He did not know about DNA, genes or chromosomes

Phenotype Actual characteristics that can be observed Physical trait that show up Examples:Height, size of feet How something looks Pheno=photo

Genotype The genetic makeup of an organism, all the genes that an organism has Geno=gene Genotype not always obvious

Principle of Dominant Dominant Allele -form that appears or shows up Covers up weaker form Recessive Allele –expressed in phenotype only when two copies of it are present in the genotype Form that seems to disappear Still carried by parent!!

On page 18 Demonstration your understanding Write your summary