5.4 Flashcards
- What are linked genes?
*Genes that are adjacent and close to one another on the same chromosome and that are inherited together are known as linked genes.
- What does map distance tell you about a pair of linked genes?
- Map distance tells you how close together a pair of linked genes is. The smaller the map distance, the closer together the genes are on the chromosome and the more likely those genes will be inherited together.
- What are sex-linked traits?
- Traits that are determined by genes located on sex chromosomes are known as sex-linked traits.
- How do sex-linked traits differ from Mendelian traits?
- Sex-linked traits differ from Mendelian traits because each parent does not contribute sex-linked alleles to every biological offspring. like with Mendelian inheritance; biological sex will determine which sex-linked alleles are inherited.
What’s special about linked traits and sex-linked traits, and how can one identify them?
Linked genes and sex-linked traits do not follow predicted ratios associated with Mendel’s laws and can be identified by quantitative analysis.
Tell me about linked genes
Typically inherited together
Less likely to be separated during crossing over in meiosis (prophase I)
How can the distance between linked traits be calculated?
The probability that genetically linked genes will segregate as a unit can be used to calculate the map distance between them.
More likely to be inherited together = closer on the chromosome
How is the probability that genetically linked traits will segregate together calculated?
- Determined by how frequently a pair of genes participates in a single crossover event
- Linked genes have a recombination frequency of less than 50%
5% is how many map units apart?
5
Which is further, 30 map units or 2 map units?
30
Are sex chromosomes homologous?
No
Why are most genetic diseases X linked?
Because the y chromosome carries very little genetic informtion
