Do you really know Genetics?
What is a tool used to show the probability of allele combinations?
A punnet square
Who created the 3 laws?
Gregor Mendel created the 3 Laws of inheritance
What is a phenotype?
The physical features exhibited, what you can see (ex: blue, brown, green eyes, etc)
You find a population of spiders that have three phenotypes: all red, all white, and red and white speckled. What is the pattern of inheritance?
Codominance
A sequence of DNA that codes for a protein that determines a trait
What is a Gene?
Males are more effected.
Who is often affected more by X-linked recessive traits?
What are Mendel's 3 Laws?
Law of Dominance
Law of Segregation
Law of Independent Assortment
What are chromosomes?
A DNA molecule that contains the genetic information for an organism.
A black coat color (B) is completely dominant in dogs. A brown coat (b) is recessive.
What is the genotype of a homozygous black dog?
The genotype is BB
What is a mutation?
Change in the DNA or chromosome sequence of a cell.
What is the number of cells resulting from meiosis?
4
What is the Law of Dominance?
When given pure parents only ONE trait will appear. The trait will be dominant.
What is a Genotype?
A set of genes for a trait (HH, Hh, hh)
In sunflowers, tallness (T) is completely dominant to shortness (t).
What are the possible phenotypes of the offspring?
What is a diploid?
A cell that has two copies of each chromosome
What does recessive mean?
A trait, only exhibited when the dominant allele is NOT present.
What is the Law of Segregation?
When you form gametes, each only receives ONE allele for each trait. Only one of the parent alleles ends up in the sperm of the egg.
What is Heterozygous?
Term for having two identical alleles for a gene. 2 of the same alleles.
Examples: HH or hh
2 heterozygous brown-eyed people are crossed. What are the possible genotypes and phenotypes of their offspring? (use the letters B/b) (Blue eyes are recessive)
Genotypes- 1 BB, 1bb, 2Bb
Phenotypes- 3 brown eye and 1 Blue eye
What is a Haploid?
A cell that has one copy of each chromosome. It also describes gametes.
What does dominant mean?
Dominant is the relationship between two versions of a gene. Also known as the trait always exhibited when the allele is present.
What is the Law of Independent Assortment?
- Goes hand in hand with the law of segregation
- The alleles separate into their gametes randomly
Inheriting one trait does NOT affect another trait(unless they are super close together on a chromosome)
This law can be demonstrated using a dihybrid cross(aka a mega punnett square)
What is Homozygous?
An organism that has two identical alleles for a trait. 2 different alleles.
Example: Hh
In a population of cats, fur color is determined by a single gene with two alleles: black (B) and white (b). Black fur (BB or Bb) is dominant over white fur (bb). If a black-furred cat (Bb) mates with a white-furred cat (bb), what are the possible fur colors and their respective probabilities among their offspring?
1. Black fur (Bb): 50% probability
The black-furred cat (Bb) can pass on the black allele (B) to half of its offspring.
2. White fur (bb): 50% probability
The white-furred cat (bb) can only pass on the white allele (b) to all of its offspring.
What is a Homologous Chromosome? And what is a Sister Chromosome?
Homologous Chromosome - Maternal and paternal copy of the same chromosome
Sister Chromatid - Identical copies of the same chromosome in duplicated chromosomes