Welcome Back Room 706 Mrs' Yarnell Biology

1
Welcome Back!Room 706- Mrs. Yarnell- Biology

• Seating Chart
• 2nd Semester Syllabus
• Restroom Passes
• EOCT Review Word Lists!
• Journal

2
Get Ready for 2nd Semester

• Word Terms / EOCT
• Warm-ups
• Genetics
• Evolution
• Taxonomy / Classification
• Ecology

3
Human Pedigrees

• Essential Question How can genetic disorders
  like hemophilia or colorblindness be traced back
  within a family?

4

• Pedigree chart- a chart that shows the phenotypes
  of a trait in a family.
• Patterns for over 2,500 inherited human
  characteristics have so far been determined.
• Show phenotype segregation in several generations
  of related individuals.

5
(No Transcript)
6
Pedigree Chart Symbols, etc.

• Squares represent males
• Circles represent females
• A horizontal line connecting a male and female
  represents the couple who will produce offspring.
• A vertical line and bracket connect the parents
  to their children.

7
Pedigree Chart Symbols, etc.

• Children should be placed oldest to youngest from
  left to right.
• An X through a square or circle represents a
  deceased individual.
• The pedigree must have a title.
• A key to explain how the trait is represented
  must be visible.
• Several generations may be shown on the pedigree.

8
Pedigree Chart Symbols, etc.

• A shaded circle or square indicates that a person
  expresses the trait.
• A circle or square that is not shaded indicates
  that a person does not express the trait.
• However, they may be a carrier of that trait!

9

• Pedigree charts show only 1 trait.
• Pedigree charts can be analyzed to infer the
  genotypes of family members.

10
(No Transcript)
11
aa albino
AA or Aa non-albino
12
Other Info about Pedigree Charts

• Marriage between close relatives results in a
  higher likelihood that both parents will be
  carriers of a rare allele and produce affected
  children.
• The major use of pedigree analysis is in clinical
  evaluation and counseling of patients with
  inherited abnormalities.

13

• Contrary to popular belief, inbreeding does not
  result in "monstrous" offspring. Marrying close
  relatives, as often occurred in royal families
  did increase the chances that recessive harmful
  alleles (like hemophilia) would be inherited.
• Inbreeding has caused many breeds of dogs to have
  harmful genetic traits. Dalmations are often
  deaf, and other dog breeds have high frequencies
  of epilepsy, blindness, and hip displaysia. It is
  true, that mutts are often hardier and have less
  health problems.

14
(No Transcript)
15

• The Story of Hemophilia
• Late in the summer of 1818, a human sperm and egg
  united to form a human zygote. One of those
  gametes, we don't know which, was carrying a
  newly mutated gene. A single point mutation in a
  nucleotide sequence coding for a particular amino
  acid in a protein essential for blood clotting.
  The zygote became Queen Victoria of England and
  the new mutation was for hemophilia, bleeder's
  disease, carried on the X chromosome.
• A century later, after passing through three
  generations, that mutation may have contributed
  to the overthrow of the Tsar and the emergence of
  communism in Russia. Victoria passed the gene on
  to some of her children and grandchildren,
  including Princess Alexandra, who married
  Nicholas II, Tsar of Russia, in 1894. By 1903,
  the couple had produced four daughters. The next
  year, the long awaited male heir appeared - His
  Imperial Highness Alexis Nicolaievich, Sovereign
  Heir Tsarevich, Grand Duke of Russia. From his
  father, the baby Alexis inherited the undisputed
  claim to the throne of all the Russias. From his
  mother, he inherited an X chromosome carrying a
  copy of the mutant gene for hemophilia. Soon
  after his birth, signs of Alexis' mutant gene
  appeared. At six weeks, he experienced a bout of
  uncontrolled bleeding and by early 1905 the royal
  physicians had concluded that he was suffering
  from hemophilia.

16
Practice Problem