Genetics and Inheritance

Question 1

Principle of Segregation/

Answer 1

Pairs of gene variants are separated into reproductive cells and zygotes get both variants (chromosomes)
- so individual has two alleles and each parent provided one allele

Question 2

Principle of Independent Assortment

Answer 2

Alleles of two different genes get sorted into gametes independent of each other for example brown eyes black hair

Question 3

Discrete Traits

Answer 3

1 gene produces 1 trait

Question 4

Define cross, parental generation (f0), filial generation(F1), Backcross

Answer 4

Cross: Two things are made to breed to produce offspring
F0: the parents used for the cross
Filial generation: the offspring from the cross
Backcross: crossing a later generation (F2) with an earlier generation (F1)

Question 5

Codominance

Answer 5

Both alleles are expressed equally, resulting in a third phenotype that includes both traits, but not blended

Question 6

Monohybrid and Dihybrid

Answer 6

Crosses cross parents that are both heterozygous for the gene of interest

Question 7

Incomplete Dominance

Answer 7

Both alleles show through, resulting in a third phenotype blended with the other two.
ex. Red flower + White Flower = pink flower

Question 8

Genotype vs Phenotype

Answer 8

genotype are alleles of particular genes

phenotype are observable traits

Question 9

Complex traits

Answer 9

Multiple influences so that it’s impossible to draw a connection between genotype and phenotype
ex height, skin colour, blood pressure and behavioural traits

Question 10

Pleiotropy

Answer 10

When a single gene has widespread effect - many diseases

ex. albinism and sickle cell anemia

Question 11

Polygenic inheritance

Answer 11

One characteristic is controlled by many genes

Question 12

Importance of pedigrees

Answer 12

• useful to track family history of a specific trait

- used tracking the patterns of inheritance of the trait:, dominant versus recessive

Question 13

Autosomal Dominant

Answer 13

• males and females carry traits equally
• never skip generations
• one of the parents must have the trait for it to be passed on to offspring

Question 14

Autosomal Recessive

Answer 14

• males and females affected equally
• possible to skip generations
• trait might not be observed in parent but offspring can have it

Question 15

X-linked recessive

Answer 15

• males are affected more than females but both can be affected
• females can pass it on to either sex
• skips generations

Question 16

X-linked Dominant

Answer 16

• males and females can be affected
• affected male means all daughters but no sons can inherit trait (pass x-chromosome to daughter)
• affected females can pass on to both sons and daughters equally

Question 17

pedigree analysis

If a trait does not skip a generation then it is…

Answer 17

Dominant

Question 18

Pedigree Analysis

If a trait has an unequal sex ratio…

Answer 18

X-linked

Question 19

Pedigree Analysis

If more males than females affected

Answer 19

x linked recessive

Question 20

Pedigree Analysis

if more females than males

Answer 20

X-linked dominant

Question 21

If the trait is not seen in both parents but is seen in their children

Answer 21

recessive