Chapter 14/15 Flashcards Preview

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Flashcards in Chapter 14/15 Deck (30):
1

Law of segregation

Two alleles for a gene segregate during meiosis into separate gametes

2

Law of independent assortment

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

3

Phenotype

Physical appearance

4

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

SRY

5

What are genes on the sex-linked chromosomes called?

Sex-linked genes

6

Epistasis

1 gene alters phenotypic expression of gene at another locus

7

Quantitative characters

Genes that vary along a continuum

8

Polygenic inheritance

Many genes affect one phenotype

9

Pleiotropy

1 gene gives multiple phenotypic effects

10

Norm of reaction

Phenotypic possibilities for a certain genotype

11

Multifactorial

Genetic and environmental factors influence phenotype

12

What are the 2 fetal testing techniques?

-Amniocentesis
-Chorionic villus sampling (CVS)

13

Barr body

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

14

Do Barr bodies inactivate independently?

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

15

Linked genes

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

16

How do nonparental phenotypes occur from linked genes?

Crossing over of homologous pairs during meiosis

17

Genetic map

Ordered list of genetic loci along a chromosome

18

Linkage map

Genetic map based upon recombination frequencies

19

Cytogenic map

Gene positions indicated with respect to chromosomal features

20

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

-Aneuploidy
-Polyploidy
-Breakage of chromosome

21

Nondisjunction

When homologous pairs do not separate normally during meiosis

22

Aneuploidy

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

23

Polyploidy

When an organism has more than 2 complete sets of chromosomes

24

Types of aneuploidy?

Monosomic
Trisomic

25

Types of Polyploidy?

Triploidy
Tetraploidy

26

Types of breakages of chromosome

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

27

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

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

28

What are the 2 exceptions to normal mendelian genetics?

1. Genomic imprinting intranucleus
2. Defective extranuclear genes

29

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

Genomic imprinting silences the maternal/paternal allele

30

How does genomic imprinting occur?

Methylation of DNA