Lecture 10

Question 1

What gene starts male development?

Answer 1

SRY gene

Question 2

What is the difference between genes and alleles?

Answer 2

Alleles are different versions of the same gene. Everyone has two alleles for a given gene. There are many more alleles for that gene in the general population

Question 3

What is hemizygous?

Answer 3

Only applies to males and their genes that are on the X chromosome with no corresponding y

Question 4

How do you draw a pedigree?

Answer 4

Put the eldest on the left hand side. Every generation on a separate line and number each generation with roman numerals

Question 5

Autosomal recessive?

Answer 5

Heterozygous unaffected.

Two heterozygous mate to have 25% chance of affected offspring

Disease can skip generations

Cystic fibrosis

Question 6

Autosomal dominant?

Answer 6

Huntington’s disease

Heterozygous affected. Homozygous generally won’t surprise.

Seen in every generation

Question 7

X-linked recessive

Answer 7

Affects homozygous females and hemizygous males.

Disease more common in males. Males cannot give trait to their sons as its on X chromosome. Every affected female will have an affected father and carrier mother. All daughters of affected male will have disease or carry it.

Eg haemophilia A

Question 8

X-linked dominant

Answer 8

Similar pattern to recessive but instead of daughters being carrier or having the disease all daughters will have the disease.

Question 9

Mitochondrial inheritance?

Answer 9

Exclusively from mother

Question 10

What is the difference between polygenic and mono genie inheritance?

Answer 10

Monogenic involves one gene while polygenic involves numerous genes

Question 11

Wha are linked genes?

Answer 11

Those on the same chromosome. Do not show independent assortment at meiosis.

At gamete formation ratios will not be even. Further apart genes are less likely to cross over together and ratio closer to 1:1:1:1

No independent assortment