How are the Principles of Probability used in genetics?
TO PREDICT THE TRAITS OF THE OFFSPRING OF GENETIC CROSSES
What is it called when an organism has 2 identical alleles for a trait?
HOMOZYGOUS
If a pea plant has a recessive allele for green peas, what will it produce if it self-pollinates?
100% green peas IF it is homozygous recessive and does not also have a dominant allele for yellow peas (the heterozygous genotype).
If a pea plant is a dwarf/homozygous recessive for height (tt), what is true about its parents?
BOTH PARENTS CONTRIBUTED A RECESSIVE ALLELE
Consider the cross TT x Tt (T = dominant for tall plant t = recessive for dwarf plant)What is true about the offspring?
ALL WILL BE TALL
Consider Tt x tt (T = dominant for tall plant). What is the probability that the offspring will be tall?
50%
How many gametes can a pea plant with the genotype RrYY form?
2 gametes (RY & rY)
Consider the cross RrYy x RRYy (R = dominant for round-shaped peas & Y = dominant for yellow color peas). How many phenotypes will be in the offspring?
2 (round-yellow & round-green)
A mule is a cross between a donkey and a horse. It is called a…
HYBRID
When doing a Punnett Square for Aa x Aa (A= normal skin pigment of a bison a = albino bison) which of Mendel’s laws do you apply?
DOMINANCE & SEGREGATION
What assorts independently?
CHROMOSOMES
Which of Mendel’s Laws states that during gamete formation genes for different traits separate without influencing each other’s inheritance?
LAW OF INDEPENDENT ASSORTMENT
Why did Thomas Hunt Morgan use fruit flies in his genetic studies?
FRUIT FLIES PRODUCE A LARGE NUMBER OF OFFSPRING
What is true about “Linked Genes”?
THEY ARE ON THE SAME CHROMOSOME (and will not assort independently)
What is it called when one allele is not completely dominant over another?
INCOMPLETE DOMINANCE
A cross of a black chicken (BB) with a white chicken (WW) produces speckled chicks.What is this type of inheritance?
CODOMINANCE
What type of inheritance yields variation in human skin color?
POLYGENIC TRAITS
Which example shows that the environment can affect genetic traits?
Hydrangea flower color varies with soil pH.
How are gametes produced?
BY MEIOSIS
How is meiosis different from mitosis?
IT FORMS HAPLOID CELLS (with ½ DNA content)
Refer to p. 324 be able to identify a graphic of Crossing Over (where chromosomes swap parts of their DNA)
a
The farther apart two genes are located on a chromosome…
THE LESS LIKELY THEY ARE TO BE INHERITED TOGETHER (The chance of crossing over increases.)
What do gametes have?
ONLY ONE ALLELE FOR EACH GENE (1/2 DNA)
-When do chromosomes form tetrads?
DURING PROPHASE I OF MEIOSIS
What is formed at the end of meiosis?
FOUR GENETICALLY DIFFERENT CELLS
If an organism’s diploid number is 12, then what is its haploid number?