Name Date Period Chapter 14 Human Genetics Take notes here Summary – one summary at the end Questions “Cornell Style”

Pedigree Analysis Studying a family tree for detection of a trait

pedigree diagram I II 123 generations birth order

pedigree symbols = male = female = mating (identical) twins(fraternal) twins = affected individual = carrier Carriers have one recessive allele and can pass the trait without expressing it.

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Sex-linked traits Inherited through genes on the X (or Y) chromosome

Sex-linked traits Example : Colorblindness – the most common is red-green

Sex-linked traits Example Hemophelia – “bleeders disease”, males 1:10,000, females 1:1,000,000

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Each human body cell has 46 chromosomes. Sex chromosomes -- determine the sex of an organism. Humans have 2 sex chromosomes X X = femaleX Y = male Autosomes -- all of the other chromosomes Humans have 44

Humans have 2 types of cells: sex and body. Sex cells are called haploid cells (n). They have 23 chromosomes. They are sperm in males and eggs in females. Body cells are called Diploid cells (2n). They have 46 chromosomes, 23 from each parent. They make your body.

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Prenatal Diagnosis Amniocentesis – small amount of fluid is removed from the sac around the embryo A karyotype is then done to ID all the chromosomes in the nucleus

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