17.2 Flashcards
What organism did Morgan need to collect evidence for an alternative theory of Mendels?
Drosophila melanogaster - fruit fly
What will the F1 generation be if you cross a white eyed male with a normal red eyed female?
The F1 generation will all have red eyes
Is the gene for eye colour in fruit flies located on the X or Y chromosome?
It is located on the X chromosome
What is the chromosome theory of inheritance?
Genes are carried on chromosomes
What are linked genes?
Genes that are found on the same chromosome
In what phase of meiosis does crossing over occur?
Prophase 1
How can alleles of two genes be on the same chromosome be found in different gametes?
Crossing over
Is a crossover most likely to occur between genes that are closer together or farther apart?
Genes that are farther apart
What does the gene-chromosome theory suggest?
The genes exist at specific sites - they are arranged in a linear manner along the chromosome
What is map distance/units?
Distance between genes on a single chromosome
What are recombinant types?
F1 generations chromosomes that have different combinations of alleles than the chromosomes of the P generations
What are parental types?
When the chromosomes of the F1 generations are identical to those of the P generation.
The percentage of recombinant types in the F1 generation corresponds to what?
The recombination frequency.
What is the percentage of the amount times that a crossover occurs as P gametes are formed?
Recombination frequency
If the gene for eye colour and wing type are 10 map units apart, what is the recombination frequency?
10%
Which colour eyes is recessive in a fruit fly?
White eyes
What are sex linked traits?
Traits that are controlled by genes on either the X or Y chromosome.
Can Y linked traits be passed to the daughter from the father?
No, only affects the sons.
What is an inactive chromosome called?
Barr body - condenses into this structure
What is a visible effect of the inactivation of the X chromsome?
Calico or tortoiseshell coat coloar in cats
What is the gene that codes for coat colour carried on in cats?
Located on the X chromosome
Are tortoiseshell cats homozygous or heterozygous?
They are heterozygous for the black and orange allele
* One X chromosome carries the black allele
* The other X chromosome carries the orange allele
What is a gene with more than two alleles said to have?
Multiple alleles
What are the alleles for blood type?
IA, IB, and i
