Biological Concepts — Lab 4 online
HUMAN GENETICS and BIOTECHNOLOGY
Instructions:
Study all the visual information in this online lab, plus the accompanying explanations.
Be prepared to answer a few "check-in" questions to show that you were paying attention.




Archibald Garrod: "Inborn Errors of Metabolism" (1906)







SOME INHERITED HUMAN TRAITS
(Somewhat simplified)


Dominant trait Recessive trait
Brown eyes Blue eyes
"Widow's peak"   (front of hairline comes
to a point over forehead) 		Straight hairline
Brachydactyly   (abnormally short fingers) Normal fingers
"Taster" of PhenylThioCarbamide (PTC) "Non-taster" of PTC
Straight thumb "Hitchhiker's thumb"


SAMPLE PROBLEMS:
 Work out each of these problems on a blank sheet of paper. List female gametes across the top (column headings) and male gametes down the left side (row headings).
These are good practice, but there is no need to hand in your answers.
  • 1. Show a cross between a man heterozygous for brown eyes and his blue-eyed wife. What fraction of their children are expected to have blue eyes?
  • 2. A brown-eyed woman has normal fingers and a blue-eyed mother. If she marries a blue-eyed man heterozygous for brachydactyly, what types of children can they expect, and in what proportions?
  • 3. A man who cannot taste PTC and has a "widows's peak" hairline marries a woman heterozygous for both traits. If their first child has a straight hairline, what are the chances that their next child will have:   (a) widow's peak?   (b) ability to taste PTC?   (c) their mother's genotype?   (d) their father's genotype?





ABO BLOOD GROUPS

Human blood groups are determined by a series of "multiple alleles": Alleles A and B are both dominant to allele o (recessive).
Alleles A and B are "co-dominant" when they occur together-- both phenotypes are expressed as blood type AB.

BLOOD TYPE Antigens Antibodies     Can give blood to: Can receive blood from: Possible genotypes:
  A   A   anti-B   A or AB   A or O   AA, Ao
  B   B   anti-A   B or AB   B or O   BB, Bo
  AB   A and B   neither   AB only   any type   AB
  O   neither  anti-A, anti-B    any type   O only   oo












MORE PROBLEMS:
  • 4. Show a cross between a man and a woman who both have blood type AB. What fraction of each blood type can they expect among their cxhildren?
  • 5. A man with blood type O marries a woman with blood type A. If their first child has blood type O, what blood types can they expect among the rest of their children, and in what proportions?
  • 6. A brown-eyed woman with blood type B has a mother with blood type O and blue eyes. If she marries a blue-eyed man with blood type AB, what genotypes can they expect among their children, and in what proportions?
  • 7. A man with blood type A and a hitchhiker's thumb marries a woman with blood type B and a straight thumb. If their first child has hitchhiker's thumb and blood group O, then what genotypes can they expect among their future children, and in what proportions?








BIOTECHNOLOGY





























CRISPR RNAs function as a viral defense mechanism in bacteria:





Application of the CRISPR-Cas system to genetic engineering:








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Click here for the
Check-In questions



——     Rev. Aug. 2020     ——