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Flashcards in Inheritance Deck (25):
1

What does a square represent on a pedigree diagram?

Male

2

What does a circle represent on a pedigree diagram?

Female

3

What does a coloured in shape represent on a pedigree diagram?

Affected individual

4

What does a diagonal line through a shape mean on a pedigree diagram

Deceased

5

What does a triangle represent on a pedigree diagram?

Miscarriage

6

What does a diamond represent on a pedigree diagram?

Unknown sex

7

What does an arrow pointing to a shape mean in a pedigree diagram?

They are the individual providing the pedigree information

8

How would you show the unborn baby of a pregnant mother on a pedigree diagram?

Draw their shape and put a P in the middle

9

What is a genotype?

The genetic makeup

10

What is a phenotype?

The physical characteristic

11

Where do an individuals two copies of each gene come from?

Mother and father

12

What does homozygous mean?

Two alleles of a gene are the same

13

What does heterozygous mean?

Two alleles of a gene are different

14

What does hemizygous mean?

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

15

What does dominant mean?

The dominant allele in a heterozygote determines the phenotype

16

What does recessive mean?

The non-dominant allele in a heterozygote is called recessive

17

What is codominance?

When neither alleles is dominant over the other e.g. A and B in blood groups

18

What are the characteristics of an autosomal recessive disease?


E.g. Who is affected? Are they affected equally? Give an example of the disease

Heterozygous is unaffected
Males and females are affected equally
Skips generations
Cystic fibrosis

19

What are the characteristics of an autosomal dominant disease?


E.g. Who is affected? Are they affected equally? Give an example of the disease

Heterozygotes are affected
Males and females are affected equally
Homozygous not viable for life
Cannot skip generations
Huntington's disease

20

What are the characteristics of a x linked recessive disease?


E.g. Who is affected? Are they affected equally? Give an example of the disease

Hemizygous males and homozygous females affected
Disease more common in males
Males cannot pass to sons
Haemophilia A

21

What are the characteristics of an x linked dominant disease?


E.g. Who is affected? Are they affected equally? Give an example of the disease

Hemizygous males and heterozygous females are affected
Affected males cannot give trait to sons but will give to all daughters
E.g. Rett syndrome

22

Who is affected by Y linked inheritance?

All male children

23

Who is affected by mitochondrial abnormalities?

Passed from mother so all of her children

24

What is abnormal about albinism?

It is polygenic so more than one gene produces the phenotype as Genes on the chromosome are linked

25

What are polygenic genes?

Do not show independent assortment at meiosis
Genes close together are tightly linked