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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

1 2 3

generations

birth order

pedigree symbols

= male

= female

= mating

(identical) twins (fraternal) twins

= affected individual

= carrier

Carriers have one recessive allele and can passthe 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 chromosomesX X = female X 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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summary about the notes.

NOT what you learned or how you feel!