Chap 14:
Mendel and the Gene
Supplemental Instruction
Iowa State University / Leader: / Julie
Course: / Biology 211
Instructor: / Dr. Holscher
Date:
  1. Many recessive ____-linked traits cause human diseases and disorders
  1. Fathers pass sex-linked alleles to all of their ______, but to none of their ______.

Ex: You’re researching color blindness in a family. You already know the parents phenotypes: The husband is color blind but the wife is not. Of their eight children, half are boys and half are girls. You know that there are 2 boys with color blindness and 2 girls with color blindness. How is this possible if only their father has colorblindness?

Ex: You realize that studying x-linked recessive traits is so much fun and decided to do more! You come across another family. The father is colorblind and the mother is not. One of their sons is colorblind also, except he is pissed about it! He hardly speaks to his father because he blames him for making him colorblind. With all your genetic knowledge how might you council this boy to help his relationship with his father?

  1. Simple Mendelian patterns may deviate when:
  2. A single gene produces multiple ______.
  3. When ______are not completely dominant or recessive.
  4. When a particular ______has more than two alleles.
  1. Most genes have multiple phenotypic effects. This is called?
  1. Describe the difference between Complete and Incomplete dominance.
  1. True or False: Dominant alleles are always more common in population than recessive alleles.
  1. Traits that are “either or” traits are referred to as what?
  1. Traits that vary in a population along a continuum creating a bell shaped curve are called what?
  1. Who was the first scientist to associate a specific gene with a specific chromosome?
  1. A normal character phenotype is referred to as what? Alternative traits are called?
  1. Morgan’s three proposed ideas:
  1. Genes are said to be ______and are inherited together as a unit called a ______.
  1. Due to ______during meiosis, ______chromosomes can exchange pieces of chromosomes and create new combinations of ______.
  2. The likely hood of a crossover occurring in the region between two genes depends on the ______between the two genes.
  1. Explain what a genetic map is? What is it based on (what makes it)?
  1. Recombination frequency
  1. True or False: The farther apart two genes are, the higher the probability that a cross over will occur?

The Challenger Question!

In a particular animal species, a long tail (T) is dominant to a short tail (t), and a blonde hair (B) is dominant to grey hair (b). When a TtBb female is mated with a ttbb male, the observed distribution of offspring is as follows 411 offspring with a long tail and blonde hair, 101 offspring with a long tail and grey hair, 312 offspring with a short tail and blonde hair, and 386 offspring with a short tail and grey hair. Based on these offspring, what is the approximate recombination frequency?