Chapter 14/15

Question 1

Law of segregation

Answer 1

Two alleles for a gene segregate during meiosis into separate gametes

Question 2

Law of independent assortment

Answer 2

One pair of homologous chromosomes moving to opposite poles does not affect the movement of other homologs

Question 3

Phenotype

Answer 3

Physical appearance

Question 4

What gene on the Y chromosome codes for development of testes?

Answer 4

SRY

Question 5

What are genes on the sex-linked chromosomes called?

Answer 5

Sex-linked genes

Question 6

Epistasis

Answer 6

1 gene alters phenotypic expression of gene at another locus

Question 7

Quantitative characters

Answer 7

Genes that vary along a continuum

Question 8

Polygenic inheritance

Answer 8

Many genes affect one phenotype

Question 9

Pleiotropy

Answer 9

1 gene gives multiple phenotypic effects

Question 10

Norm of reaction

Answer 10

Phenotypic possibilities for a certain genotype

Question 11

Multifactorial

Answer 11

Genetic and environmental factors influence phenotype

Question 12

What are the 2 fetal testing techniques?

Answer 12

• Amniocentesis

- Chorionic villus sampling (CVS)

Question 13

Barr body

Answer 13

Because there are 2 X chromosomes in a sex-linked homolog, one X chromosome condenses into a Barr body

Question 14

Do Barr bodies inactivate independently?

Answer 14

Yes

Either maternal/paternal can condense. Embryo ends up having 1/2 maternal inactivated and 1/2 paternal inactivated

Question 15

Linked genes

Answer 15

Two or more genes on the same chromosome that are physically connected and sort dependently

Question 16

How do nonparental phenotypes occur from linked genes?

Answer 16

Crossing over of homologous pairs during meiosis

Question 17

Genetic map

Answer 17

Ordered list of genetic loci along a chromosome

Question 18

Linkage map

Answer 18

Genetic map based upon recombination frequencies

Question 19

Cytogenic map

Answer 19

Gene positions indicated with respect to chromosomal features

Question 20

What are the three types of chromosomal alterations (2 are abnormal chromosome number)

Answer 20

• Aneuploidy
• Polyploidy
• Breakage of chromosome

Question 21

Nondisjunction

Answer 21

When homologous pairs do not separate normally during meiosis

Question 22

Aneuploidy

Answer 22

Fertilization of gametes in which nondisjunction of a homolog has occured in a gamete

Question 23

Polyploidy

Answer 23

When an organism has more than 2 complete sets of chromosomes

Question 24

Types of aneuploidy?

Answer 24

Monosomic

Trisomic

Question 25

Types of Polyploidy?

Answer 25

Triploidy

Tetraploidy

Question 26

Types of breakages of chromosome

Answer 26

1. Deletion
2. Duplication
3. Inversion
4. Translocation

Question 27

Klinefelter syndrome (XXY) and Turner Syndrome (XO) are the result of what?

Answer 27

Aneuploidic sex chromosomes. In Klinefelter, sex chromosome is trisomic, and in turner syndrome, sex chromosome is monosomic

Question 28

What are the 2 exceptions to normal mendelian genetics?

Answer 28

1. Genomic imprinting intranucleus

2. Defective extranuclear genes

Question 29

When the phenotype passed down depends on which parent passed down the allele, what is happening?

Answer 29

Genomic imprinting silences the maternal/paternal allele

Question 30

How does genomic imprinting occur?

Answer 30

Methylation of DNA