D.N.AIn humans, the allele for

dimples (D) is dominant. The allele for not having dimples (d) is recessive. A woman (DD) and a man (Dd) have four children. Which of these if the predicted ratio of the children with dimples to the children without dimples?

D

d

D

D

DD DD

Dd Dd

a.1:0b.1:1c.1:3d.3:1

IN ORDER TO DETERMINE WHETHER A DISEASE OR TRAIT WILL BE PASSED TO FAMILY MEMBERS, A PEDIGREE IS CREATED

PEDIGREE

A PEDIGREE CHART Is a map of a family’s genotypes It can be used to trace a disease or interesting

trait through a family

A square represents a male

A circle represents a female

If it is filled in, means the male or female has a trait

Effected Female Effected Male

Uneffected male

Uneffected female

If it is unfilled in, means the male or does not express the trait or is

homozygous recessive

A horizontal line between a circle and a square means that they are married

If there is a line coming down from the connected couple, it

means they have children

HOW MANY MALES ARE THERE IN THE FAMILY?HOW MANY FEMALES ARE THERE IN THE FAMILY?HOW MANY PEOPLE IN THE WHOSE FAMILY HAVE THE DISEASE?WHAT IS THE SEX OF THE PARENT WHO HAS THE DISEASE?

67

4

Female

IN HUMANS, THE ALLELE FOR HAVING FEET WITH NORMAL ARCHES IS DOMINANT (A). THE ALLELE FOR FLAT FEET IS RECESSIVE (A). THE PEDIGREE BELLOW SHOWS THE OCCURRENCE OF NORMAL ARCHES AND FLAT FEET IN FOUR GENERATIONS OF A FAMILY. IN THE PEDIGREE, INDIVIDUALS ARE IDENTIFIED BY THE GENERATION AND INDIVIDUAL NUMBERS.