Cycle 5 (Workshop + Study Session) Flashcards
Define:
Alleles
Variation in genome sequence
Define:
Homologous allele
Same locus
Assign gene and allele for the following trait:
Eye colour
Gene: Eye color
Allele: Blue
During ________ ____, _______ can switch between __________ ___________
Crossing over
Alleles
Homologous chromosomes
Is this true:
Alleles for the same trait are always on different spots on the same chrromosome
False, alleles for the same trait are always on same spot on the same chromosome
True or False:
Homologous chromosomes can carry the same or different alleles
True
What is it called when homologous chromosomes can carry the same or different alleles?
Homozygosity or heterozygosity
Define:
Dominant allele
Only need one copy of allele to express phenotype
Define:
Recessive allele
Need both copies of allele to express phenotype
How is the dominant and recessive allele determined?
By observing the phenotype of the heterozygote
What was the Blending Theory? How is it flawed?
Blending theory of inheritance was in the 1800s, stated that offspring have characteristics of both parents, therefore they must be a blend of both parents
Does not explain dominant and recessive traits
State the Law of Segregation
Alleles segregate randomly into gametes
50% chance that either alleles end up in a gamete
What does Mendel’s model comprise of?
Punnett’s square
Law of segregation
What does Mendel’s model fail to explain?
Codominance and incomplete dominance
Define:
Incomplete Dominance
Heterozygotes have intermediate expression
Define:
Codominance
Both alleles are equally expressed in heterozygotes
What is it called when the trait may be carried on either the X or Y chromosome?
Sex-linked
Sex linked traits most commonly on the _ chromosome
X
Define:
Epistasis
One gene interferes with expression of another gene expression
Is epistasis a Mendelian inheritance?
No
Define and give examples of:
Mendelian Inheritance
Dominant-Recessive Genes
Both alleles fully expressed, dominant allele masks the recessive allele
Monohybrid (Aa) Crosses Phenotypic Ratio, 3:1
Dihybrid (AaBb) Crosses Phenotypic Ratio, 9:3:3:1
Define and give examples of:
Non-Mendelian Inheritance
Polygenic Traits
Epistasis
Codominance
Incomplete dominance
Sex-linked inheritance
Define:
Polygenic traits
Many genes work together to form 1 phenotype
What is the phenotypic ratio for epistasis?
9:3:4 (AaBb)