Chapter 12: Genes, Chromosomes, and Human Genetics

Question 1

Linked Genes

Answer 1

When two genes are close together on the same chromosome

Question 2

Genetic Map

Answer 2

Describes the methods used to identify the locus of a gene & the distance between the genes

Question 3

Chromosome Map

Answer 3

Is a DNA test that allows the tester to determine which segments of DNA came from which ancestor

Question 4

Wild-type

Answer 4

Refers to the phenotype of the typical form of species as it occurs in nature

Question 5

Test cross

Answer 5

Involves breeding a phenotypically dominant individual with a phenotypically recessive individual

Question 6

Map Unit

Answer 6

The unit of a linkage map (mu). Is a equivalent to a recombination frequency of 1%

Question 7

Sex-linked genes

Answer 7

Gene located on a sex chromosome. One or more pairs of chromosomes are different in males and females

Question 8

Autosomes

Answer 8

Chromosomes other than a sex chromosome

Question 9

X & Y chromosome

Answer 9

These are the two sex determining chromosomes. X X is female, and X Y is male

Question 10

Pedigree

Answer 10

The reconstruction of genotype and phenotypes of past generations from family records

Question 11

Haemophilia

Answer 11

Are bleeders because if they are injured they bleed uncontrollably. A protein required for forming blood clots is not produced in functional form

Question 12

Barr Body

Answer 12

Inactive X chromosomes in a females somatic cell

Question 13

Deletion

Answer 13

Occurs if a segment is broken from one chromosome

Question 14

Duplication

Answer 14

Occurs if a segment is broken from one chromosome and inserted into its homologue. In the receiving homologue, the alleles in the inserted fragment are added to the ones already there

Question 15

Translocation

Answer 15

Occurs if a broken segment is attached to a different, non-homologous chromosome

Question 16

Inversion

Answer 16

Occurs if a broken segment reattaches to the same chromosome from which it was lost, but in reversed orientation, so that the order of genes is reversed

Question 17

Nondisjunction

Answer 17

The failure of homologous pairs to separate during the first meiotic division

Question 18

Aneuploid’s

Answer 18

An abnormal # of chromosomes in the cell, such as having 45 or 47 chromosomes when 46 is expected

Question 19

Euploid’s

Answer 19

Individuals that have normal sets of Chromosomes

Question 20

Triploids

Answer 20

Fetuses with Triploid syndrome have an extra set of chromosomes in their cells

Question 21

Polyploid

Answer 21

Cells and organisms that contain more than two sets of chromosomes

Question 22

Down syndrome

Answer 22

Humans that receive an extra copy of chromosome 21

Question 23

Trisomy 21

Answer 23

Causes Down syndrome, and it is the smallest human chromosome

Question 24

Turner Syndrome

Answer 24

Is a condition in which a female is partly or missing an X chromosome