HDF 303 Lecture Notes - Lecture 4: Down Syndrome, 100 Girls, Teenage Pregnancy
25 Sep 2016
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Document Summary
Genes segments of dna located along the chromosomes. Dna substance of which genes and chromosomes are made. Identical/monozygotic one zygote that divides into two individuals. Occurs more often among women whose mothers and sisters gave birth to fraternal twims . Rises with maternal age , peaking between 35 and 39 years, and then rapidly falls. Occurs less often among women with poor diets; occurs more often among women who are tall and overweight or of normal weight as opposed to slight body build. Examples of dominant and recessive characteristics (table- not in notes, shown in class) About 106 boys are born for every 100 girls, worldwide. In recent decades, the proportion of male births has declined in many industrialized countries, which many researchers attribute to a rise in stressful living conditions. Chemical marker that activates either father"s or mother"s gene. Risk of down syndrome and all chromosomal abnormalities by maternal age (table- not in notes, shown in class)
