Genotype, Phenotype And Inheritance Flashcards Preview

ESA1 - Medical Cell Biology and Genetics > Genotype, Phenotype And Inheritance > Flashcards

Flashcards in Genotype, Phenotype And Inheritance Deck (30)
Loading flashcards...
1

What is meant by genotype?

An organisms genotype is the set of genes that it carries

2

What is meant by phenotype?

The observable characteristics of an organism

3

What is genetics the study of?

Inheritance and variation

4

How many alleles of a particular gene does each individual have?

2

5

What is the meaning of homozygous?

Two alleles of a gene are the same

6

What is the meaning of heterozygous?

Two alleles of a gene are different

7

What is the meaning of hemizygous?

Only one allele of a gene on the X chromosome (so males only)

8

Which alleles are dominant in terms of blood type?

Allele A dominant over O
Allele B dominant over O
Allele A and B are co dominant

9

How would you identify an autosomal recessive trait?

Heterozygotes unaffected

Males and females equally affected

Can skip generations, seems to come out of nowhere

Both parents of affected individual are heterozygous carriers

10

How would you identify an autosomal dominant trait?

Heterozygotes affected

Males and females equally affected

Rarely found in homozygous state

Every affected individual has at least one affected parent, cannot skip generations

11

What is an example of an autosomal recessive disease?

Cystic fibrosis

12

What is an example of an autosomal dominant disease?

Huntingtons disease

13

How do you identify an X linked recessive trait?

Males and females unequally affected

Every affected male has at least a carrier mother

Every affected female has affected father and carrier mother

Affected males have at least carrier daughters

Affected males cannot give trait to sons

14

What is an example of an X linked recessive disease?

Haemophilia

15

How is albinism inherited?

Recessive

16

How many genes does each huma have?

25,000

17

What is the percentage of two heterozygotes having affected offspring?

25%

18

How is Huntington's disease inherited?

Autosomal dominant

19

How is Cystic Fibrosis inherited?

Autosomal recessive

20

How is Haemophilia A inherited?

X-linked recessive

21

Why are X-linked diseases more common in males?

Only need one copy of X chromosome to be affected while females need two

22

Why can't affected males of X-linked conditions give the trait to their sons?

Father can only give Y chromosome to offspring

23

True or Flase:

With X-linked conditions, every affected male will have at least a heterozygous mother.

True!

24

Will the daughters of men with X linked conditions be, at least, carriers?

Yes

25

What is an example of an X linked dominant condition?

X-linked hypophosphatemia (type of rickets)

26

What is an example of a Y-linked condition? (very rare)

Retinitis Pigmentosa (night blindness)

27

What are genes on the same chromosome said to be?

Linked

28

What do linked genes not show?

Independent assortment at meiosis

29

What is recombination frequency between two linked genes dependent on?

The distance between the genes

30

What can be used to calculate allelic frequencies and therefore ratios of frequencies in a population?

Hardy-Weinberg principle