Mendelian Genetics

Question 1

This states that genes segregate at meiosis so that each gamete contains only one of the two possessed by the parent.

Answer 1

Law of Segregation

Question 2

This states that alleles of different genes assort independently during gamete formation.

Answer 2

The Law of Independent Assortment

Question 3

When a gene has many alleles.

• these allelic variations are usually due to mutations

Answer 3

Polymorphic

Question 4

This is when F1 has intermediate phenotype. But F2 includes parental phenotypes.

Intermediate phenotype refers to when the dominant phenotype is expressed in a reduced ratio - giving off the idea that it is a “blended” phenotype.

• usually results in new heterozygous phenotype

Answer 4

Incomplete dominance

Question 5

This is when both phenotypes exist side by side within an organism.

• phenotype produced is distinctive
• parental phenotypes are present in F1

Answer 5

Co-dominance

Question 6

These are traits by which the phenotype is controlled by many genes that have an additive effect. Characters appear continuous/quantitative

• a trait which is controlled by multiple genes (eg., height/skin colour)
• several genes contribute to the final phenotype

Answer 6

Polygenic traits

Question 7

The more genes involved in polygenic traits then the..

Answer 7

higher number of phenotypic classes. Wider genetic variation because it gives way to multiple different phenotypes being created.

Question 8

How does the environment smooth differences between phenotypes?

Answer 8

By having a controlled environment that will select for favorable phenotypes

Question 9

These are traits determined by the sex chromosomes.

Answer 9

X linked traits

Question 10

What happens to an affected father’s offspring? (mode of inheritance)

Answer 10

• all daughters would be affected (as one x chromosome comes from dad and one from mum)
• no sons would be affected

Question 11

What happens if a carrier mother mates with a normale male? (mode of inheritance)

Answer 11

There is a 50% chance that her daughters and sons would get it

• as her daughters would either receive XX (with normal X of both parent) or X(a)X which would make them carriers
• sons would either receive XY (normal XY from both parent) or X(a)Y which would make them affected

Question 12

What happens if a carrier mother mates with an affected male? (mode of inheritance)

Answer 12

• daughters without the disorder = carriers
• sons would be affected
• but SOME sons would be completely free of harmful allele (because they inherit normal XY chromosomes)

Question 13

This occurs during meiosis and produces recombinant offspring.

Answer 13

Recombination

Question 14

This is the frequency of recombinant genes in a population.

Answer 14

Recombinant frequency

Question 15

The smaller the distance between two genes (in a chromosome) then…

Answer 15

The less likely a chiasmata will form in between them.

Question 16

Why are recombinant frequencies higher in wider distances between genes?

Answer 16

Because a chiasmata is more likely to form between distant genes - and therefore establish recombinant genes and produce recombinant types in the population

Question 17

These are genes located next to or close to each other on a chromosome.

Answer 17

Linked genes