The Genetics of SEX DETERMINATION

Klinefelter Syndrome

Klinefelter Syndrome

________** (XXY)- has an additional X chromosome at chromosome 23.

Symbols

________ are used to represent different aspects of a pedigree such as the following.

Polydactyl baby

________ is born with one or more extra fingers, cleft palate.

Pedigree Analysis

________- Used to study the inheritance of genes in humans.

Sila ung

________ may both male and female reproductive organs.

Females

________ carry a U chromosome, whereas males carry a V chromosome.

Genes

________ on the X chromosome have different patterns of expression in females and males.

Translocations

________- involves the movement /change of location of a segment of a chromosome to a new place in the genome.

causative allele

Linked recessive trait is if the ________ is present in two copies.

Philadelphia Syndrome

________- deletion of an arm on chromosome 21.

Tay Sachs Disease

________- multiple kinds of mutations in chromosome 15.

Inversions

________- a segment of a chromosome is turned around 180 degrees.

Patau Syndrome

________- addition of 1 chromosome on chromosome 13, 14 or 15.

sexual category

The father determines the ________ of the offspring.

holandric inheritance

Also known as ________, is the determination of a phenotypic trait by an allele (or gene) on the Y chromosome.

Family Pedigree

________- Shows the history of a trait or illness in a family.

Prader Willi Syndrome

________- deletion of the arms in chromosome 15; respiratory problems, bird- like head, obese.

Dominant x

________- linked conditions and traits are rare and gene expression differs between the sexes.

Duplication

________- a condition where there is duplication of chromosomes.

twenty third pair of chromosomes

The ________ is different and determines sex.

Phenotypic sex

________ also has a couple of distinct systems: the internal ducts, and the external genitalia.

Y chromosome

Chromosomal sex- Presence or absence of the ________.

human traits

Allows geneticists to analyze ________ and /or diseases.

Sex-determination system

a biological system that determines the development of sexual characteristics in an organism

Ex

King Henry VIII

Gonadal sex (primary sex determination)

whether the gonads develop as testes or ovaries depends on the presence or absence of the SRY gene, usually found on the Y chromosome

phenotypic sex (secondary sex determination)

all of the internal and external structures develop along male or female lines depending on which hormones are secreted by the gonads

Phenotypic sex also has a couple of distinct systems

the internal ducts, and the external genitalia

Two important times

pre-natal development and puberty

Males have two different sex chromosomes

X and Y chromosome (XY)

Chromosomal Aberration

Any range resulting in the duplication, deletion, or rearrangement of the chromosome material

**Klinefelter Syndrome (**XXY)

has an additional X chromosome at chromosome 23

**Turner Syndrome (**X0)

individuals have only 1 X chromosome

broad, shield

like chest

Poly X (Superfemale, Metafemale)

individuals have more than 2 X chromosomes (XXX)

i. Monosomy

loss of 1 chromosome

Cri-du-chat syndrome (cry of the cat)

deletion of chromosome 5 lower arm

Trisomy

addition of 1 chromosome

Down Syndrome (Mongoloid)

addition of 1 chromosome on chromosome 21

Edward Syndrome

addition of 1 chromosome on chromosome 16, 17 or 18

Patau Syndrome

addition of 1 chromosome on chromosome 13, 14 or 15

i. Deletion/ Deficiency

a condition where a portion of a chromosome is lost; breaks in the chromosome

Philadelphia Syndrome

deletion of an arm on chromosome 21

Duplication

a condition where there is duplication of chromosomes

Inversions

a segment of a chromosome is turned around 180 degrees

Translocations

involves the movement/change of location of a segment of a chromosome to a new place in the genome

Tay-Sachs Disease

multiple kinds of mutations in chromosome 15

13 Q Deletion Syndrome

deletion of the lower arm of the chromosome 13

Aniridia-Wilms Tumor Syndrome

deletion of the upper arm of the chromosome 11; blindness, kidney tumor, mentally retarded and retarded growth

18 Q Deletion Syndrome

deletion of the arms on chromosome 18; heart diseases, large eyes and ears but normal lifespan

Prader-Willi Syndrome

deletion of the arms in chromosome 15; respiratory problems, bird-like head, obese

ZW Sex Chromosomes

found in birds, some reptiles, and some insects and other organisms

The ZW sex-determination system is reversed compared to the XY system

females have two different kinds of chromosomes (ZW), and males have two of the same kind of chromosomes (ZZ)

UV Sex Chromosomes

In some Bryophyte and some algae species

Mendelian Genetics

Pedigree Analysis

Pedigree Analysis

Used to study the inheritance of genes in humans

Family Pedigree

Shows the history of a trait or illness in a family

In females, X-linked traits are passed just like autosomal traits

that is 2 copies are required for a recessive allele, and one for a dominant allele

X

linked recessive trait is if the causative allele is present in two copies