Slide 1KaryotypeGenesChromosome PairsChromosome Pairs (cont.)Autosomes and Sex ChromosomesBoy Meets GirlWe All Start Out As…Chromosomes and Human GeneticsKaryotype•A picture of your chromosomes at metaphase•Why not another phase of mitosis? –Chromosomes are easiest seen in metaphase•Answers questions about chromosome abnormalities •Cultured “in vitro” which means: in glass–The opposite term for a living body test is called ___ _____Genes•Genes- GENEtic information at a certain spot on the chromosome•Gene locus- The LOCation of a gene•Alleles- Alternative form of a gene•Homologous chromosomes- a pair of chromosomes that contains genes for the same trait, one from ma and one from paChromosome Pairs•We have 46 chromosomes that are like volumes of two sets of books•Chromosomes 1-22 are called autosomes•Chromosomes 23 is called the sex chromosomes•Chromosomes 1-22 are paired and both pairs have the same length and shape.Chromosome Pairs (cont.)•The pairs of chromosomes carry the same hereditary instructions for the same traits•Your father gave you one set, your mother another set –but hers was an alternative edition from your father’s •Her set covers the same topics, but are slightly different for many of the instructionsAutosomes and Sex Chromosomes•Autosomes are 22 pairs that are not the sex chromosomes•Autosomes are the same in both sexes•The sex chromosmes are the 23rd pair•Sex chromosmes come in two varities: X and Y•XX = Female XY = MaleBoy Meets Girl•Both sexes have an _____ chromosome•The X chromosome has more than 2,300 genes•MOST of the X chromosome are nonsexual traits (such as blood clotting)•The Y chromosome has fewer than 24 genes–One is the MASTER GENE for male determinationWe All Start Out As…•Females•The Master gene determines if a person will become male, if it is not present then the person becomes a _________•So the mother or father determines the sex of the