Vocabulary Heredity and Genetics

Heredity and Genetics Vocabulary Trait – A characteristic caused by genetics or the environment Chromosomes – Long strands of DNA that contain thousands of genes Genes – Part of chromosome that controls a trait(30,000 in humans) Allele – Different forms of genes Recessive allele – Only see this trait if two are present Dominant Allele – Always shows its trait Hybrid – Has two different alleles for same trait Purebred – Has two identical alleles for same trait Probability – The likelihood that an event will occur Punnett Square – A chart that shows all possible combinations of alleles between two organisms Phenotype – The visibly expressed trait (ie. blue eyes) Genotype – The allele combination for a trait (ie. Bb or bb.) Homozygous – Two identical alleles (Purebred) Heterozygous – Two different alleles (Hybrid) Codominant Alleles – Neither allele is dominant(ie. Blood types or spotted dog) Incomplete Dominance – The dominant alleles mix – (Green flower from blue and yellow alleles) Meiosis – Process that creates sex cells with one copy of each gene or half the number of chromosomes Cross-Fertilization – A gamete(sex cell) from each parent gives one allele for each trait to make a new organism(humans) # of human chromosomes – 23 pairs or 46 chromosomes X and Y – Human chromosomes that determine gender Mutation – When a chromosome is not copied correctly Carrier – Someone who has one recessive allele for a trait but doesn’t show it. Pedigree – A chart that tracts a particular trait in a family Karyotype - A picture of all the chromosomes of a cell Genome – All the DNA in one cell of an organism Genotype – An analysis of a genome to determine inherited traits Gene therapy – The insertion of a corrected gene into a person to try and correct a problem. Genetic Engineering – Transferring a gene from one organism to another to produce a new trait. (ie. Glowing Frog) Selective breeding – Only mating organisms with desirable traits. Clone – An organism that is genetically identical to the parent organism DNA – Deoxyribonucleic acid – The molecule that is the base of all chromosomes Four bases of DNA – Adenine and Thymine; Guanine and Cytosine Heredity – The passing of traits from parent to offspring Sex-linked Gene – A gene that is on the X or Y chromosome(hemophilia or color blindness) Gregor Mendel – A monk in the 1850’s that studied how plants inherit traits Crick and Watson – Two scientist who first described the DNA double-helix molecule Genetic Disorders – Illnesses or disorders caused by an abnormal gene (Examples: Downs and Turner Syndrome -wrong number of chromosomes, Recessive traits - Sickle Cell Anemia, Cystic Fibrosis) Inherited Trait – A trait totally controlled by your genes (ie. Eye color) Environmental Trait – A trait that is expressed as a combination of your genes and the environment. (ie. Skin color) Epigenetics – How genes are turned on or off by their environment GM Foods – Organisms that have been genetically modified for farmers. (rice that produces more grain)