5.3

Question 1

Family tree diagrams (Pedigrees)

Answer 1

know how to draw them
- horizontal lines between people is fucking
- double line means incest
- vertical lines to progeny (kids)
- horizontal line above progeny arranged left to right in order of birth
- diagonal lines for twins
- circle is female
- square is male
- colored symbol means affected

Question 2

which is smaller, X or Y chromosome?

Answer 2

X

Question 3

how do X and Y chromosomes pair

Answer 3

they are largely non-homologous, so only the tips share homology to allow them to pair and segregate

Question 4

Genes on the Y chromosome

Answer 4

78 genes for roughly 25 proteins, and about half help determine sex

Question 5

How many genes on the X chromosome and main 2 X-linked genes

Answer 5

1100 genes, mostly unrelated to sex determination
X-linked genes:
- red-green colour blindness (recessive, more common in XY)
- haemophilia, blood clotting disorder (recessive)
those two are also linked to eachother (close together on chromosome, 12 mil bp or 12 map units apart)

Question 6

name of genes on sex chromosomes

Answer 6

sex-linked genes

Question 7

Hemizygous

Answer 7

only one allele for that gene
eg: red-green colour blindness in men caused by recessive allele on X chromosome

Question 8

will linked genes always be inherited together?

Answer 8

no, because of crossing over
crossing over can occur in XY but typically only in the pseudoautosomal region, otherwise problems tend to occur

Question 9

names of crossed over vs non-crossed over chromosomes

Answer 9

recombinant vs nonrecombinant

Question 10

High-density linkage maps

Answer 10

use SNPs in non coding regions that are in high association to disease/other gene as marker alleles to determine the likeliness the individual has a gene and approximately where the gene is

Question 11

linkage maps

Answer 11

examining the frequency of two genes presenting together to determine how close they are on the chromosome