Inheritance: basic laws and test cross

Question 1

It reflects the ACTIONS OF CHROMOSOMES and the genes they carry DURING MEIOSIS. A diploid individual possesses a pair of alleles for any particular trait and EACH PARENTS PASSES ONE of these randomly to its offspring.

Answer 1

Law of Segregation

Question 2

It states that for TWO GENES on different chromosomes, the inheritance of one gene DOES NOT influence the chance of inheriting the other gene.

Answer 2

Law of Independent Assortment

Question 3

These are the patterns in which SINGLE-GENE TRAITS and DISORDER OCCURS IN FAMILIES.

Answer 3

Modes of Inheritance

Question 4

OFFSPRING has the SAME TRAIT as a parent.

Answer 4

True breeding

Question 5

It carries the SAME ALLELES TT or tt.

Answer 5

Homozygous

Question 6

It carries DIFFERENT ALLELES Tt.

Answer 6

Heterozygous

Question 7

ORGANISM’S ALLELES.

Answer 7

Genotype

Question 8

The outward EXPRESSION OF AN ALLELE combination.

Answer 8

Phenotype

Question 9

Most COMMON PHENOTYPE.

Answer 9

Wild Type

Question 10

The OBSERVED TRAIT is?

Answer 10

Dominant

Question 11

The MASKED TRAIT is?

Answer 11

Recessive

Question 12

Recessive traits are due to…

Answer 12

Loss of Function

Question 13

Dominant traits are due to…

Answer 13

Gain of Function

Question 14

Mendel’s laws can appear NOT TO OPERATE when ONE GENE masks or otherwise AFFECTS the PHENOTYPE OF ANOTHER.

Example: Bombay Phenotype

Answer 14

Epistasis

Question 15

It refers to the PERCENTAGE OF INDIVIDUALS who have a PARTICULAR GENOTYPE have the associated phenotype.

Example: Polydactyly

Answer 15

Penetrance

Question 16

It refers to VARIABILITY IN SEVERITY of a phenotype or the extent to which the gene is expressed.

Example: Polydactyly

Answer 16

Expressivity

Question 17

A SINGLE-GENE DISEASE with many symptoms, or a gene that controls SEVERAL FUNCTIONS or HAS MORE THAN EFFECT.

Example: Marfan Syndrome

Answer 17

Pleiotropic

Question 18

Mutations in DIFFERENT GENES produce the SAME PHENOTYPE.

Example: Osteogenesis Imperfecta

Answer 18

Genetic Heterogeneity

Question 19

An environmentally CAUSED TRAIT that appears to be inherited.

Example: Infection

Answer 19

Phenocopy

Question 20

Genetics refers to the TRANSMISSION OF GENES on the SAME CHROMOSOMES.

Answer 20

Linkage

Question 21

What type of mutation is ALBINISM?

Answer 21

Autosomal Recessive Trait

Question 22

What type of mutation is Polydactyly?

Answer 22

Autosomal Dominant Trait

Question 23

These are SYMBOLIC REPRESENTATIONS of FAMILY RELATIONSHIPS and the TRANSMISSION OF INHERITED TRAITS.

Answer 23

Pedigree

Question 24

A phenotypic class DOES NOT SURVIVE TO REPRODUCE.

Example: Achondroplasia

Answer 24

Lethal Alleles

Question 25

MANY VARIANTS or DEGREES of a phenotype are possible.

Example: Cystic Fibrosis

Answer 25

Multiple Alleles

Question 26

A heterozygote’s phenotype is INTERMEDIATE BETWEEN those of the TWO HOMOZYGOTES.

Example: Familial Hypercholesterolemia

Answer 26

Incomplete Dominance

Question 27

A heterozygote’s phenotype is DISTINCT from and NOT INTERMEDIATE BETWEEN those of the TWO HOMOZYGOTS.

Example: ABO Blood Types

Answer 27

Codominance