Sex-Linked, Multiple Alleles & Future of Genetics

How many genes does the x chromosome hold?

The X chromosome holds about 2000 genes, meaning that most sex linked traits are carried on the X chromosome.

How many Genes does the Y chromosome hold?

Less than 100 genes

What does the allele for a sex linked trait look like?

The allele on the sex chromosomes is shown as a superscript to an X or Y. 
X^HX^h

What are the sex chromosomes for Males and Females?

Males: XY

Females: XX

Why do males only have one allele for x linked genes

Males have one X chromosome and one Y chromosome, which usually do not carry the same genes.

Why can females have 2 alleles for X-linked genes?

Because females have two X chromosomes, so they can have two copies of a gene found on the X chromosome.

Where do Males get their X chromosome from?

Males get their X chromosomes from their Mother.

Why are males more affected by X linked traits?

This is because males only have one X chromosome, so there is no second X allele to cover up for the other one if it has a recessive trait.

Are the genes on X and Y chromosomes the same?

No. X and Y chromosomes carry different genes, so usually the Y chromosome is unable to cover the X chromosome in the case of a recessive gene and can result in X-linked recessive disorders.

If a male inherits an X chromosome with a recessive trait, why might he show the trait?

Because he has only one X chromosome, so there is no second X chromosome to mask the recessive allele.

What are the two types of Chromosomes?

1. Somatic Chromosomes (autosomes)

2. Sex Chromosomes

Somatic Chromosomes:

Carry the same gene (trait) but has different alleles (THIS IS CHROMOSOMES 1-22)

Example: Chromosome 7 might carry eye colour, one might be blue and the other might be brown depending on the parent

Sex Chromosome

Determine an individual's sex, and may carry sex-linked traits. There are two types: X and Y chromosomes. Found on Chromosome 23.

What does the Y Chromosome determine? How is it passed along?

Y - Linked genes can only be transmitted from father to son and contains about 100 genes, usually being involved in determining male sex determination and development.
EXAMPLE:
1. Y Chromosome Infertility (defect) results in complete or partial failure to produce sperm, leading to low production of sperm

4 Blood Types

1. Type A (Type A Carbohydrate Molecules on red blood cells.)

2. Type B (Type B Carbohydrate Molecules on red blood cells.)

3. Type AB (Type A & B Carbohydrate Molecules on red blood cells.)

4. Type O (No Type A or B Carbohydrate Molecules on red blood cells.)

What genetic inheritance does Blood type A and B together make?

Codominance

Blood type A + Blood type O

Blood Type A is dominant over Blood type O

Blood Type B + Blood Type O

Blood Type B is dominant over Blood Type O

Blood Type O is…

Recessive

Human Genome Project

A research initiative that aimed to map and understand all the genes of the human species, took place from 1990 - 2003.

Helped to

1. Identify

2. Map

3. Sequence

4. Determine the base pairs that make up DNA

Genomics

is the study of genomes and the complex interactions of genes that result in phenotypes 

What is Bioinformatics?

Uses computer technology to create and analyze large databases of information. Specifically focuses on genomics and molecular biology.
Created By Margaret Dayhoff

Genetic profile:

the complete genotype of an individual, including various mutations

What can you do with Genetic profiling?

1. Genetic counsellors & doctors will be able to give more specific risk assessments

2. Design individualized prevention plans

3. Design genetically precise treatment programs.

Who should have access to the genetic profile?

1. Could insurance companies deny coverage to people who have a genetic liability for a particular disease?

2. Could potential employers have access to an individual’s genetic profile and use it in assessing whether to hire the person?

3. Should researchers be allowed to use the genetic profiles of individuals to help them better understand the link between the genome and phenotype?

4. Could potential individuals date according to the genetic profile?