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Chromosomes and Human Genetics. Karyotype. 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
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Karyotype • 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 pa
Chromosome 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 instructions
Autosomes 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 = Male
Boy 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 determination
We 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 child?