Sex-Linked Traits & Pedigree Analysis

Vocabulary flashcards covering key terms on sex-linked inheritance, sample disorders, problem-solving tools, and pedigree interpretation from General Biology 2 Unit 1 Lesson 1.3.

Sex-linked trait

Any genetic characteristic controlled by genes located on a sex chromosome (X or Y), with expression influenced by the individual’s biological sex.

X-linked trait

A trait whose gene is located on the X chromosome; can appear in both sexes but more often affects males.

Y-linked trait

A trait whose gene is located on the Y chromosome; passed exclusively from father to son.

X-linked recessive inheritance

Inheritance pattern in which a recessive allele on the X chromosome causes the trait to be expressed in males and in homozygous females, while heterozygous females are carriers.

Carrier (genetics)

An individual who possesses one copy of a recessive allele for a trait or disorder but does not express the phenotype; can pass the allele to offspring.

Hemophilia

An X-linked recessive bleeding disorder, historically called the “Royal Disease,” in which blood fails to clot properly due to missing clotting factors.

Color blindness

An X-linked recessive condition that impairs the ability to distinguish certain colors, typically red and green.

Hypertrichosis Pinnae Auris

A Y-linked trait characterized by excess hair growth on the outer ear margins, inherited only from father to son.

Punnett square

A grid diagram used to predict the genotypes and phenotypes of offspring from a genetic cross.

Genotype

The genetic makeup of an organism, representing the specific alleles present.

Phenotype

The observable characteristics or traits of an organism resulting from its genotype and environmental influences.

Genotypic ratio

The proportional distribution of different genotypes produced in a genetic cross.

Phenotypic ratio

The proportional distribution of observable traits among offspring in a genetic cross.

Pedigree analysis

The study of an inherited trait in a family tree over multiple generations to determine its mode of inheritance.

Pedigree symbol: carrier

A half-shaded circle (female) or square (male) representing an individual who carries one recessive allele for an X-linked trait.

Autosomal trait

A characteristic determined by genes located on the non-sex (autosome) chromosomes; inheritance is not dependent on sex.

Tongue-rolling trait

An autosomal dominant trait where the ability to roll the tongue is dominant over the inability to do so.

Royal pedigree of hemophilia

Historical family tree tracing the spread of hemophilia from Queen Victoria through European royal families, illustrating X-linked recessive inheritance.