Many areas of expertise overlap into other subjects and as such, an expert in one field will be able to make an educated guess in another. If you don't have the skill in question, you can use a relevant skill at a penalty.
Accounts : knowledege -5 or maths -3
Acrobatics : agility -3 or athletics -2
Acting : comms -3 or fast talk -2
Aerodyne Tech : tech -4 or suitable mechanic / vehicle tech skill -2
Aircraft Tech : tech -4 or suitable mechanic / vehicle tech skill -2
Archery : manipulation -4
Astrogation : knowledge -5, astronomy -2 or planetology -3
Astronomy : knowledge -5, astrogation -2 or planetology -3
Athletics : agility -3
Biology : knowledge -6
Biotech : tech -6, biology -4 or cybertech -3
Botany : knowledge -6
Chemistry : knowledge -6, biology -4 or pharmacy -2
Climbing (Freefacing) : agility -4 or any other climbing skill -2
Climbing (General) : agility -4 or any other climbing skill -2
Climbing (Mountaineering) : agility -4 or any other climbing skill -2
Command : communications -3
Computer Use : knowledge -3, programming -2, decking -2
Contacts (type) : no defaults, you know people or you don't :-)
Culture (type) : no defaults
Cycle : agility -3
Dance (style) : agility -2
Decking : knowledge -6 or computer use -4
Demolitions : tech -5
Detect Lies : knowledge -2, communications -1 or psychology -0
Disguise : tech -4
Drive : manipulation -4
Electronics (general): tech -6, electronics (computers) -4 or electronics (cybertech)
-3
Electronics (computers) : knowledge -6, computer use -3 or electronics (general)
-2
Electronics (cybernetics) : knowledge -6, computer use -3, electronics (general)
-2 or biotech -3
Electronics (communications) : knowledge -6, electronics (computers) -4 or operate
(communications) -3
EVA : agility -5
Evaluate : knowledge -4 or related tech skill -2
Facilities (type) : no default
Fast Talk : communications -4 or acting -2
First Aid : tech -5, medtech -3 or surgery -1
Forgery : tech -4
Gambling : knowledge -2
Geology : knowledge -5
Heavy Weapons : manipulation -5 or rifle -4
Hide : any of agility, sneak or shadowing all at -1
History : knowledge -3 (maybe a suitably related tech or expert skill at -2
at ref's discression)
Interface : knowledge -5 or decking -3
Interrogate : communications -3, command -2 or intimidate -1
Interview : communications -2 or interrogate -2
Intimidate : communications -2 or interrogate -1
Intrusion : knowledge -6, computer use -4 or decking -2.
Investment : knowledge -2 or accounts -2
Language (specific) : no defaults
Law : knowledge -4
Library Use : knowledge -2, computer use -2 or literary study -1
Literary Study : knowledge -4 or history -3
Locksmith : tech -4 or security -2
Maths : knowledge -1
Mechanic : tech -2
Melee (Hand weapons) : manipulation -2
Melee (blades, one handed) : manipulation -3 or blades (2H) -2
Melee (blades, two handed) : manipulation -4 or blades (1H) -3
Melee (clubs, One handed) : manipulation -2 or clubs (2H) -1
Melee (clubs, two handed) : manipulation -3 or clubs (1H) -2
Melee (Polearms) : manipulation -4
Melee (Whips/jointed) : no default
Occult : knowledge -4 or literary study -3
Operate (ommunications) : tech -2 or electronics (communications) -1
Operate (medtech) : tech -4 or surgery -2
Operate (sensors) : tech -2 or electronics (general) -1
Perception (type) : perception -0
Perform : communications -3, public speaking -2 or acting -1
Pharmacy : tech -6 or chemistry -3
Physics : knowledge -4 or maths -2
Pick Pocket : tech -2
Pilot (Aerodyne) : manipulation -4 or rotor -3
Pilot (Aircraft) : manipulation -4 or spaceplane -2
Pilot (GEV) : manipulation -3
Pilot (Micro-remotes) : manipulation -2
Pilot (Parawing) : manipulation -3
Pilot (Rotor) : manipulation -4 or aerodyne -3
Pilot (Ship) : manipulation -5
Pilot (Spaceplane) : manipulation -5 or aircraft -4
Pilot (Tug) : manipulation -5 or spaceplane -3
Pistol : manipulation -3 or other firearm skill -2
Planetology : knowledge -4 or geology -3
Play (instrument) : no default
Programming : knowledge -6, decking -5, electronics (computers) -5 or computer
use -4
Psychology : knowledge -5 or communications -4
Physiology : knowledge -5, surgery -3 or diagnose -2
Public Speaking : communications -2, perform -1 or acting -1
Research : knowledge -3 or library use -1
Resistance : no defaults
Rifle : manipulation -3 or other firearm skill -2
Rotor Tech : tech -6, mechanics -3 or pilot (rotor) -2
Scrounge : communications -2
Security : tech -4 or locksmith -2
Seduction : communications -1
Shadowing : any of agility, hide or sneak at -1
Ship Tech : tech -5, mechanics -4 or pilot (ship) -3
SMG : manipulation -3 or other firearm skill -2
Sneak : any of agility, hide or shadowing at -1
Sniping : no defaults
Spacecraft Tech : tech -5, mechanics -4 or pilot (spaceplane / tug) -3
Specialist (type) : no defaults
Stim Recording : no defaults
Streetwise (type) : no defaults
Style : no defaults
Surgery : tech -5, first aid -4 or diagnose -3
Survival (Space) : knowledge -3
Survival (Urban) : knowledge -3
Survival (Wilderness) : knowledge -3
Swim : agility
Systems (type) : no defaults
Teach : no defaults
Track : perception -1 or shadowing -2
Unarmed Combat (type) : no defaults
Video : no defaults
Weaponsmith (type) : tech -3 (or electronics (general) -2 for high tech devices
- lasers, gauss, smartscopes, etc).
Write : knowledge -1 or literary study -0
Zerobatics : agility -2
Zoology : knowledge -3