Genetics and Heredity

Genetics and traits Genetics: the study of how certain features are passed from parents to their offspring Trait: a distinguishing quality that all members of a species have in common (eyes, chin, etc.) Variations: Different forms of the same trait (blue/brown/or green eyes, cleft chin)

Traits Heredity: the passing of traits from parents to offspring. Heredity plus your environment will work together to influence who you will become – “Nature Vs. Nurture Which do you think bear a greater impact on your development?

Reproduction and Heredity Four basic methods of asexual reproduction: – 1.Rooting: a cutting is taken from a mature plant and rooted to create a new plant (often used to get desirable traits in agriculture) – 2.Spores: like seeds can grow into new organisms – 3.Budding: small bud forms on the parent and breaks off to form a new organism’ – 4.Fission: (most common) dna is copied, cell divides, new cell membrane encases new daughter cells

Sexual Reproduction Requires male and female cells (sperm and egg) called gametes. Does asexual or sexual reproduction generate greater variety? Sexual reproduction creates greater variety due to a greater variety of trait possibilities. Traits are passed from parent to offspring in the form of genes Genes: small segment of DNA that carries hereditary info.

Genes Genes have all info needed to build, maintain, and reproduce an organism. Genes link together to form chromosomes Organisms’ cells can read the codes in chromosomes just like we read a book

Genetic Code

Genetic Code/Traits Some genes determine on trait: – Straight hairline or widow’s peak – Earlobes are attached or free – One gene-one trait

Genetic Code/Traits Some genes can influence several traits – Marfan syndrome is caused by a single gene and it affects the heart, eyes, ligaments, and muscles – One gene-multiple traits

Genetic Code/Traits Some traits are the result of the interaction of many genes – Skin color and finger prints – Multiple genes-one trait

On Your Own Take a few moments and quietly read pages

Dominant and Recessive Recessive Trait: the weaker of two traits offered when two parents produce an offspring. Dominant trait: the stronger of these two traits. Alleles: different forms of a single gene

Dominant and Recessive Genotype: The combination of an organism’s dominant and recessive alleles for a trait. Homozygous: an offspring that has the same allele from both parents for a particular gene Heterozygous: an offspring that has different alleles from each parent for a particular gene.

Dominant and Recessive Phenotype: the observable traits of an organism.