L1-3 quiz

• if the dominant allele G determines green pod colour and the recessive allele g yellow pod colour, what proportion of the progeny would have green pods in a cross Gg X gg?

  50%
• if the recombinant frequency between genes A and B is 10%, between A and C is 2.5%, and between B and Cis 9.5%, the relative order of the genes on the chromosome is

  A-C-B
• the largest recombination frequency is between 2 genes that therefore must lie on the outside of the map
• in a cross AaBbCCdd X AaBbCcDd, what is the probability of finding the genotype aaBBCCdd in the progeny?

  1/64
• in a cross Yy X Yy, the ratio is 2:1 rather than the expected 3:1, the phenomena involved in this cross are:

  pleiotropy and a lethal allele
• pleiotropy is when 2 seemingly unrelated traits are both affected 


  such as coat colour and viability
• lethal allele means that:


  organism carrying the allele will die due to the allele
• In sweet peas, P = purple flowers and p = white flowers, C = purple flowers and c = white flowers so that a plant with the genotype PPcc will have white flowers, as will a plant with the genotype ppCC. In a cross between plants heterozygous for both genes, what ratio of purple flowers to white flowers would you expect in the progeny?

  9:7
• chromosomes failing to separate during meiosis, leads to a condition in which the diploid number is not normal, phenomenon is called:

  nondisjunction
• The genes for white eyes and yellow bodies are both situated on the X chromosome of Drosophila. Assuming that w is recessive for white eyes, w+ dominant for red eyes, y recessive for yellow bodies and y+ dominant for grey body colour, what is the recombination frequency in percent between these two genes from the following data derived from a cross between a female heterozygous for both genes and a male with white eyes and a yellow body: 97 white and yellow, 2 white and grey, 2 red and yellow, 99 red and grey.

  2.0%
• the photo shows 


  continuous variation

  
• synaptonemal complex develops in early meiosis
• synaptonemal complex is a lattice of proteins that holds homologues together and allows crossing over to happen
• Mendel's experiment:

  • parents have alternative forms of the same trait
  • hybrid plants were produced which displayed only one f the alternative parental characteristics
  • hybrid plants were self-pollinating
  • parents were always true breeding (homozygous)