Inheritance

Question 1

Dominant

Answer 1

Allele that is always expressed (represented by uppercase) (ie B)

Question 2

Allele

Answer 2

different forms of the same gene

Question 3

Gene

Answer 3

part of a chromosome that controls a certain trait

Question 4

Recessive

Answer 4

Allele that is only expressed when there is no dominant allele (represented by lowercase) (ie b)

Question 5

Genotype

Answer 5

the genetic code of an individual (BB, Bb, bb…)

Question 6

Phenotype

Answer 6

physical expression of genes (brown hair vs blonde hair)

Question 7

Homozygous genotype

Answer 7

same allele (BB, bb)

Question 8

Heterozygous genotype

Answer 8

different alleles (Bb, Ab) (Capital always first)

Question 9

Heredity

Answer 9

Heredity is basically how the genes are brought down from generations to generations

Question 10

Law of Dominance

Answer 10

There are two factors (alleles) (so 2 alleles) for every trait (every gene) that are passed down from generations

• One allele is dominant over another.

Question 11

Law of segregation

Answer 11

Every gene is controlled by 2 alleles, one allele is passed on from each parent offspring.

Question 12

Law of Independent Assortment

Answer 12

Alleles for different genes are passed on independently
and randomly to the next generation.

In other words: Passing on Trait 1 does not affect how
Trait 2 is passed on

Ex. If a parent passes on a brown eye allele to their offspring, it
doesn’t affect what allele for hair colour they pass on

Question 13

Punnett Square

Answer 13

A square chart we use to predict the offspring

Question 14

Incomplete dominance

Answer 14

Incomplete dominance is a genetic phenomenon where the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes, resulting in a blending of traits.

Question 15

Codominance

Answer 15

Codominance is a genetic inheritance pattern where both alleles of a gene pair are fully expressed in the heterozygous condition, resulting in a phenotype that displays characteristics of both alleles

Question 16

Sex-Linked genes

Answer 16

23rd pair are sex chromosomes which determine the gender of the offspring

Female = xx

Male = xy

Offspring will always be 50/50

Question 17

Y Chromosome

Answer 17

X and Y chromosomes in males are homologous for only their part of their length since the y chromosome is a lot shorter than the x chromosomes

The Y chromosomes therefore cannot carry all the corresponding genes which are on the x chromosomes

Question 18

Intersex

Answer 18

Intersex individuals are born with sex characteristics such as chromosome patterns, gonads, or genitals that do not conform to traditional definitions of male or female.

Question 19

Inheritance pattern

Answer 19

the transmission of traits/diseases to the offspring

Question 20

Autosomal Recessive

Answer 20

Involves recessive allele on a non-sex chromosomes

• skips generations
• Affects male/females equally
• Pedigree may or may not show carriers

Hint: Look for an affected from unaffected parents

Question 21

Autosomal Dominant

Answer 21

Involves a dominant allele on a non-sex chromosome

• There will not be carriers
• Not skip generations
• Affects males/females equally
• Every affected child will have an affected parent

Question 22

X-linked recessive

Answer 22

Involves a recessive allele on the X-chromosome

• More males affected than females
• Skips generations

(When a female is affected, so the father must have the trait)