Chapter 6 Flashcards
The transmission of genes close to one another on the same chromosome violates which of Mendels laws
The law of segregation
What is synteny
When two or more genes are located on the same chromosome and are physically linked
What is genetic linkage
When genes close together on a chromosome tend to be transmitted as a unit which influences inheritance patterns
What causes genes that are far apart to independently assort
Crossing over
Linkage is altered during prophase one of meiosis due to crossing over. What do replicated sister chromatids associate as and what do non sister chromatids do
Bivalents
Non sister chromatids exchange dna segments
Crossing over may produce recombinant genotypes
In haploid cells what is true regarding linkage
They contain the same combination of alleles as the original chromosomes
The arrangement of linked alleles doesn’t alter in gametes
Without crossing over there can be no recombination
What is a non parental or recombinant cell
Haploid cells that contain a combo of alleles not found in the original chromosome
How are recombinant offspring produced
The exchange of dna between two homologous chromosomes during meiosis in one or both parents leading to new genetic material
According to one of Morgan’s hypothesis why might all three genes be inherited together
They are all on the X chromosome
What other major hypothesis did Morgan have
Crossing over results in new combos of alleles
The likelihood of crossing over depends on the distance between the two genes with a higher probability toward genes farther apart
What does each gene have
Its own unique locus
Why do we do genetic mapping
To determine the linear order of linked genes along the same chromosome
What is the map distance equation
Number of recombinant offspring divided by total number of offspring multiplied by 100
What is a test cross
An individual that is heterozygous for two or more genes is crossed to one that is homozygous recessive for the same genes
What can test cross data be used for
Estimating the distance between two genes
A test cross is expected to yield a maximum of only 50 percent recombinant offspring
